DO THE TON

Blood Sweat Tears and Grease => Projects => Specials => Topic started by: doc_rot on May 18, 2015, 23:13:53

Title: saving a 1980 KZ750 twin
Post by: doc_rot on May 18, 2015, 23:13:53
I originally picked this bike up for a buddy, who vastly underestimated what it would cost to get this thing on the road.  The PO did the usual dumb stuff, needless to say it did not run and alot of stuff needed attention. It also has no title. As as started working on it for my friend I fell in love with the looks of this engine, and when he decided it was too much of a financial obligation i bought it off him. Despite the engines external appearance it is squeaky clean inside, and when i checked the valve clearance everything was at optimal spec and it has great compression. I'm starting to think the odometer may be correct and that there is only 4500 miles on the motor. this is what i bought it as...

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0306_zps414c1005.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0305_zpsf984e4e7.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0308_zpseecf9457.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0309_zpsec35cbda.jpg)

I know what some of you may be thinking, "Finish your damn kz1000 project first!". I am moving to california in a couple months and apparently registering a no title bike there is a nightmare, its not easy in Washington, however its pretty straight forward. So the plan is to fix what needs fixing, triage some of the stuff i want to do so I don't have to do it twice, get it inspected by the state patrol, and register it before I move so I can start the 3 year probationary period for the title.

Im getting pretty close to being ready for the inspection.  I plan to use a lot of the parts that i originally intended to use on my kz1000 before that went a completely different direction. I'm gonna be doing it in a style that has been done to death; aka Go Takamine, Wrenchmonkess.... etc, i think it suits big twins well, and do some small performance mods. Also i want to do some of the stuff guys are doing on their kz1000's  like bracing the frame and beefed up motor mounts. Down the road I'd like to send my cams out to megacycle for a regrind, do a port and polish, and get some hot carbs.

Parts i already have slated for use are:
New engine covers - the early twin style, the PO trashed the existing with a flap wheel.
KZ650 spoked wheels - lighter than the stock mags, rear bored out to take 20mm axle.
Avon Roadriders -  in the factory sizes, 3.25x18 and 4.00x18
Aluminum Works shocks -  these are setup for a kz1000 so likely will need to be revalved/ different springs, they are rebuildable
GS1100E swingarm -  shortened to the stock 750 length
tarrozi fork brace
kz1000 forks - rebuilt with progressive springs
KZ1000 LTD fender

I got a chinese TIG welder a couple months ago and have been welding like its a part time job to practice up. Turns out my buddy is not only a great welder he's an excellent teacher, so I have picked it up pretty quick. I'm proud to say I have done all the fabrication on this bike, except the aluminum work on the swing-arm, don't have much practice with aluminum yet.

Ill let the pics do the talking from here

(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0862_zpss445enfl.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0693_zpscdxqqvle.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0830_zpsu438ccjb.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0673_zpshngrelke.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0740_zpshclj3rn6.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0750_zpsqvpua6np.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0795_zpsnoc3sh9q.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0797_zps93wdrfuk.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0792_zpstptflmsm.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0808_zpspryxt2kg.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0812_zpssba8ymcn.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0872_zps1imghbuw.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0868_zpsdepqnao8.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0864_zpswhjil6hh.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0866_zpshiliuwvw.jpg)

(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0823_zpsiod5tdkq.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0818_zpsqcej3utz.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0826_zpsokeznm8l.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: PNWRider on May 19, 2015, 01:10:04
Looks great so far! Really want to find myself a 750 twin
Title: Re: saving a 1980 KZ750 twin
Post by: Bootsey on May 19, 2015, 03:03:48
Looks like a good project - after seeing your work on the KZ1000, definitely looking forward to following your progress.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 22, 2015, 06:48:40
Ill get some better photos of this when its done. still needs shock mounts, torque link mount, chain rub, chain guard mount, and a zerk on the pivot tube. (where were you on that Suzuki?)

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0880_zpssx24u5cq.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0881_zps0imixfn3.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0882_zpsdyozfprt.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0883_zpsvdhk1y2d.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 22, 2015, 18:59:27
I have been reading up on artificial aging with aluminum to return strength.  For a precipitation heat treatment of 6061  you do 6-20 hours at 320F°. Or 6-10 hours at 350F° I know the stock gusset in between the arms is a different alloy because it reacted very differently to the NaOH. it stayed bright while the arms turned dark like 6061 does. Some alloys aren't heat treatable, so it may not make a difference for that but i figure its better than nothin.  My neighbor is a chef and has a commercial oven in her house that she has agreed to let me use to bake this thing. Im going to use a rockwell gauge to see how hard it is before and after, mostly for my own curiosity.

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 24, 2015, 05:53:58
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0886_zpsqgod0dhi.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0891_zpsfb8ql7b4.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0887_zpsd83fopxw.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0889_zpsfsklapxp.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 25, 2015, 07:47:56
Adventures in aluminum...  other than some practice beads, this is the first aluminum piece i have ever fabricated/welded myself. I am loving this welder.
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0897_zpsfozmeyea.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0898_zpsi8ccu8fl.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0899_zpsbqirxncm.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0900_zpsh4nldgy9.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0901_zpstdmou7ml.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0902_zpsddtf2t7f.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0903_zpsfhchpxyx.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0905_zpszpwug3ny.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 27, 2015, 06:54:35
Seat is coming along. The top is finished and i have the sides basted on before doing th real seam. I dont really like making seat covers, they stress me out.
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0906_zpsj50mmqdv.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0907_zpsxsdhq3fr.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0910_zpsnec0engm.jpg)

I revised the mounts on the taillight and it is finished. i probably will paint it black, lol.

(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0914_zpsvwmktbek.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0918_zps8p9jqjbd.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0919_zpswkbalwkk.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0920_zpshyglvswl.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0921_zpsgxxwuazw.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0922_zpslswvu6u6.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_0923_zps8wecfovc.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on May 27, 2015, 12:11:42
Well Howdy Dudy Mang! Nice work on the TIG time, been working with my Chia TIG also, once you have the setups dialed for materials and sharpen a dozen electrodes for those blind oop welds it's so much cleaner than the hot glue gun... dab don't poke!

Not a fan of the two hole Kowi but I'm sure it will pull it's weight  :o Sweet light bracket remake.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 27, 2015, 19:29:12
Thanks Tune. I don't know how I will like the bike, Never ridden the 750 twin before, so like a dumbass i'm going to put a lot of time and money into something I may dislike. I do love the looks of the engine though, particularly the clutch cover.
 
On an awesome note, State Patrol contacted me yesterday telling me they had an opening in the schedule today if i would like to come in early for an inspection. Called in sick to work, then cobbled some shit together making sure all the lights and brake worked, and passed the inspection.   8)  The officer didn't even look at the bike she was just interested in the VINs, so i probably didn't need to stay up till 5 am troubleshooting the lighting system. Now i can register it and start the 3 year probation period for the title. Stoked!
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on May 27, 2015, 19:55:36
Damn Doc, you are knocking this outa the park.  I love the kz twins.  I have an 81' I'm rebuilding slowly.   Your tail light rocks.  Nice skills.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 29, 2015, 03:25:28
Thanks man. The kz750 twin is a strange beast. definitely the black sheep of the kawi lineup of the time.

did the first pass on the side panel today but I'm almost out of thread . Im sweatin doing the final fold seam where the quilted part meets the side, that seam is over 4 ft long.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on May 29, 2015, 08:46:18
Heck yeah.  Killer work all around.  What kind of machine are you using?  Standard or an industrial with a walking foot?  They can be a struggle, and getting through a big seam like that on one needle is close.  They usually want to pop pop pop about 3/4 in.  I'm still trying to figure some of that out.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 29, 2015, 18:11:03
Thanks, I'm using an old Husqvarna machine that my mother bought in  1975. Im actually quite impressed by how well this machine handles multiple layers of foam and vinyl. I have been thinking about splitting the seam into two passes and sewing a small piece of cording in the back to cover where they join.

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0261_zps5b5e7601.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 30, 2015, 04:40:54
Tonight I finally mounted the courage to attempt the fold seam, had a couple beers and went for it. It came out pretty good, not as nice as i would have hoped but i'm cool with it. I ended up splitting the seam into two chunks, and undid the rear seam to insert some webbing to cover up where the two sides meet. I cut the excess out of the cover and stretched it on the pan with tape so i can make sure that my pattern for the boxing section at the front is still good. In the pic of the webbing on the back you can see some small holes where i removed a seam, i thought i sewed inside those but guess i didn't. i have some vinyl repair stuff that will make them virtually undetectable.  ::) I don't want to ever make another seat, they stress me out too much, some things are better left to the pros.
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on May 30, 2015, 05:36:44
Wow bud, you are doing some really nice work and turning out some really neat stuff here.
Title: Re: saving a 1980 KZ750 twin
Post by: jeffw on May 30, 2015, 13:12:14
Looks great so far been trying for the last couple of years to pick up 750 twin but not much where live.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 30, 2015, 16:55:34
Thanks guys. I had never seen a 750 twin in person prior to this, kinda rare.
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on May 31, 2015, 06:59:49
My wife is gonna attempt the seat cover for her CL100.  Upholstery leather.  What brand/type thread are you using?

BTW the seat you are making is mind blowing. 

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 31, 2015, 15:25:25
thank you. Not sure of the brand but i'm using a 92 weight polyester thread. its super strong.

this is exactly what im using, except i get it locally for 1/3rd the price, so I'd shop around
http://www.amazon.com/Thread-Polyester-Bonded-Thread-4-Spools/dp/B00EZCP4GO/ref=pd_sim_201_1?ie=UTF8&refRID=02CBEZDVR1J02D6TZ6G5
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on May 31, 2015, 16:55:03
Thanks dude,  Ill tell her to check fabric store.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 28, 2015, 01:47:47
I have been super busy trying to finish up two bikes to sell so that has been occupying my time. I finally finished the seat, but i still need to rivet a few more places to get the edge to be even. Very pleased with how everything turned out considering this is only the second seat i have ever made. The tricky part was getting the seam on the seat to align with the stripes on the tank. The side covers mounts were badly cracked so when i repaired those with fiberglass i extended the edge to fill the gap between the frame. Next up is to finish the swingarm, make spacers for the wheel and arm. and do a little frame bracing.

(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_1022_zpsjxrhfdcm.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_1027_zpszq8qyd1x.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_1024_zpsoklqtus9.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_1029_zpsbi49lcve.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_1031_zpshesmcf18.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/twin/IMG_1030_zpsug289yfo.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 28, 2015, 04:46:21
Thinking about how i want to detail the engine. paint n the engine was done very poorly so i'm going to soda blast it off. i might paint the cylinders and head black. with everything else bare or polished. Thinking about doing the polished fin edge if i do them black. but it kinda looks funny with few fins getting the treatment in one spot. Maybe ill do the fin below as well. thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Jun 28, 2015, 05:45:19
seat looks fantastic!

either polish all the edges or none.  half looks exactly like what it is...half assed.  ;)

And try to grind the fins on jugs so they are close to the same thickness as the fins on the head.

Otherwise you end up w thick polished edges on the head and thin on the jugs...looks allright, but not as nice.

Fins on my 360 jugs were like knife blades.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 28, 2015, 06:41:06
I dunno, sometimes i see the cylinder done as well and i think its a little over the top. I did just a proper job polishing them back and i think it looks a lot better. still up in the air though. kinda reminds me of the new thurxton.

Title: Re: saving a 1980 KZ750 twin
Post by: Bootsey on Jun 28, 2015, 06:46:09
Just polishing the head fins looks OK, I think it works better with some colour scheme than others. Any idea of what colour you're going with on the tank & side covers?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 03, 2015, 20:38:46
Not sure on the color yet. I am super wishy washy when it comes to color. I was thinking maybe a dark cherry red, or an off white? The other day i saw this old suburban that was kinda this green-gold color... Ill just do everything else black and neutrals that way i can change the body color at will.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 03, 2015, 20:59:21
Doc, I dig that last pic of the heads with the top fins sanded and it works with the polished valve cover.   The alloy look will extend through to the carbs. 
Title: Re: saving a 1980 KZ750 twin
Post by: jking9312 on Jul 12, 2015, 19:50:32
I've had more bikes than I can count, many KZ's, and my favorite was a 79 KZ 750t LTD. That thing just fit me like no other and felt so nimble. I wish I had it back........

Sent from my SM-G900V using Tapatalk

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 22, 2015, 04:43:56
I did a little bit of frame bracing. Im debating putting the one in from the back bone to the subframe. there is loads of room between the tank and seat here, and i think it would benefit by it. Thoughts?

(http://i735.photobucket.com/albums/ww356/VictorWilkens/20150722_001405_zpswappmayu.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/20150722_001417_zpslx5clrjm.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/20150722_001428_zpsddez2cfh.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/20150722_001451_zpsvdjr27r4.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 22, 2015, 12:20:45
You have a bunch of good bracing in there.  I would think the one from the subframe to the arched backbone would be overkill at this point.  Unless you go all Evel Knievel with it. 
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 23, 2015, 16:04:11
You have a bunch of good bracing in there.  I would think the one from the subframe to the arched backbone would be overkill at this point.  Unless you go all Evel Knievel with it.

lol, this is sitting  out in the garage...
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 23, 2015, 16:06:06
I mounted a road rider on the rear wheel, and dropped the bike off at my buddies shop. I just made him a seat for his BMW project, so for trades he is going to make me some wheel/swingarm spacers, and help me finish the swingarm fabrication. Cant wait to see the swingarm finished! heres a pic of his beemer.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 23, 2015, 18:09:08
lol, this is sitting  out in the garage...

That is awesome.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 29, 2015, 03:45:54
My buddy had some time to turn up the wheel spacers. The swingarm is a perfect fit in the the 750 twin frame, nothing needed there. While he was messing around with that i used his buffer to polish up the new engine covers. I personally prefer the older style text, and since the ones on this motor are pretty trashed its was a good excuse to switch.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 30, 2015, 16:54:34
I whittled down the shock mounts. Eric hogged out the axle plate and welded them in. the torque link mount is welded in as well, as are the chain guard mounts. We had to cut a chunk out of the gusset in the middle to provide clearance for the wheel since the arm was shorted and inch and a half. I hope to have some free time on sunday to go back and polish the swingarm out on his buffer, figure out the chain slider situation, and get some good pics of it in the sun.  Once i get it home i am going to measure the geometry, and reevaluate. I may need to swap for different triple or move the upper shock mounts. we will see. I'm stoked!

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1443_zpsmxfs7sse.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1447_zps8qobtg7y.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1448_zpsmwmkz21t.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1449_zpsutxp6qqw.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1451_zps5gbcvz5l.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_4351_zpsjqfpboyt.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Jul 30, 2015, 20:51:36
Dude, that mother fucker b sweet!  sorry bout the language.  but i think that best describes it.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 03, 2015, 08:00:21
i noticed when i was buffing the stator cover that part of the casting was broken off, not surprising since it looked like someone beat on it with a hammer at some point. I welded it up and started to polish it out. I also brought the bike home form my buddies shop. I didn't have time to buff out the swingarm yet. I couldn't resist and mocked it up real quick... things are taking shape  8)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1464_zpsxpdnfmlj.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1479_zpslz98z7sn.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1469_zpsbxxfmguq.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1470_zpsrcutuegp.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1474_zpsanlqq1jv.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1476_zpsmpzyckeq.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1478_zpsnu0vylol.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Aug 03, 2015, 08:15:02
Wow, it just keeps getting better and better.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Aug 03, 2015, 12:01:29
Beauty Doc, that swingarm is the bomb man...
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 06, 2015, 09:22:26
Thanks for the kind words guys.

 I got the motor pulled last night, finished welding the braces in the frame, removed and added some tabs, and will be dropping the frame off for powder this afternoon
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 06, 2015, 22:39:28
BLING! 8) 8)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 19, 2015, 07:09:07
Cases are polished, I painted the jugs and head and cleaned up the fins. Couple things left to polish before its done. Any suggestions on replacements for wire clamps that go under the case bolts?
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1301_zpsg9ats9pt.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_0834_zps88v7dnf5.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: Brodie on Aug 19, 2015, 07:38:35
Maybe a P clamp? Come in a heap of different sizes and materials.

(http://industrialhyd.com.au/userfiles/image/accessories%20pics%20002.jpg)

Also, engine looks rad dude.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 20, 2015, 19:41:51
got a little photo happy, but im so pleased with how it turned out, and even more pleased I dont have to polish anymore. My custom bolts/spacers came in for the close tolerance motor mounts as well.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Aug 20, 2015, 23:30:29
That engine looks amazing.   Love your build. 

Hey, seen this one?

http://thebikeshed.cc/2015/08/04/the-pacific-motorcycle-co-n-zed/
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 21, 2015, 03:45:55
Thanks dude. thats the bike that made me consider the backbone to subframe brace. its very nicely done. particularly like the primaries of the exhaust, I think the one I make will be something like that but with longer mufflers.
Title: Re: saving a 1980 KZ750 twin
Post by: redwillissuperman on Sep 05, 2015, 23:23:38
BLING! 8) 8)

How did you sand and buff the swingarm?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 06, 2015, 17:14:07
I hit it with some 320 and a medium soft block, then used my buddies stand alone buffer.


Title: Re: saving a 1980 KZ750 twin
Post by: jcw on Sep 06, 2015, 20:47:14
Great skills, and beautiful work.

I'm no engineer but I've read than heating and welding aluminum takes the temper out of it.
I think 6061 in the annealed state has a rather low yield strength.

What do you think?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 06, 2015, 23:33:57
I appreciate the concern. Yes, 6061 does loose its temper when welded. I am planning on doing some artificial aging to help return some of the strength. I am aware that this is less than ideal, however, I am not terribly worried because the early aluminum swing-arms from Suzuki were not heat treated post weld (this is off a '82 GS1100). Furthermore, Its fairly common practice to lengthen aluminum swing-arms and no one heat treats. The guy that did the welding has done loads of aluminum swing-arm mods over the years and has never had an issue. Once I start riding the bike I will be scrutinizing the welds for cracks. If any cracks appear I will probably build a new swing-arm from scratch so I can use the appropriate filler rod so it can be heat treated. In retrospect I should have done that in the first place, as it wouldn't have cost me much more money but it would have been substantially more time.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Nov 06, 2015, 02:26:38
Mate, what an amazing set of skills!  Really loving your work.  I dont know many people that can weld like that AND throw together a seat cover like that.  Kudos.

Wheres this project at now?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Nov 06, 2015, 05:26:27
in storage for the moment.  unfortunately, hopefully i will have a chance to pull it out in 6 weeks. I have been building the skill set to make some trick headers in the interm. fun on the bridge port, and a too hot fusion weld right here
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Nov 06, 2015, 09:13:47
I like the blue 1/16" tungsten for Ti and if you can flood some argon under the welds you want to look nice
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 05, 2016, 06:12:36
I never seem to have any free time to work on the bikes these days. I did make a little progress this week and started assembling everything. The motor is in the frame, the new motor mount bolts are super snug and made getting the engine in there a challenge. I still need to make the mount plates.

 I put new bearings in the swingarm, added a grease fitting, and I started the chain slider. After a couple failed attempts I got a sheet of Delrin to melt over a piece of the tube I capped the swingarm with. It ended up being a bit thinner than i would have liked but it turned out pretty nice. I need to mount it to the arm next. Should I rivet it or drill and tap for some counter sunk screws?

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1929_zpsa9lsfbrv.jpg)

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1927_zpsfmqxoa8v.jpg)

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1928_zpsi4lm11yy.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Jan 05, 2016, 08:49:15
maybe just some removable plastic push rivets, if the wear just replace them
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Jan 05, 2016, 20:04:20
maybe just some removable plastic push rivets, if the wear just replace them

+1  they would be perfect in this application.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 08, 2016, 06:41:26
Its a ROLLER.
Also got the body work in sealer.
I couldn't find any countersunk rivets and the push rivets i could find locally were way to big, so i got impatient and ended up counter sinking some 3mm allen screws for the chain slider. I sunk them below the plastic height so hopefully they'll be protected a little bit.

Much to my chagrin the new wheel is 3 lbs heavier than the stock wheel and tire - which was bald enough that the new wheel probably is more like only 2 lbs heavier than the stock. Its a push on overall weight though because the swing arm made up the difference. The geometry is a little more aggressive than i would like as well.I didn't account for how much height the mount on the swingarm would add to the "shock to axle" length. With both these things happening it seems like the perfect excuse to swap for something like a aluminim 17" rim with a 130/70/17 tire and a stainless spoke kit. Hindsights a mofo

I pulled the dual disk setup off my roached KZ650 that some asshole torched a couple months ago. The fire burnt the MC but everything else was untouched. Its funny, This dual setup was on my first KZ1000, that i then put on my second KZ1000, then on my kz650, and now its going on this bike. At least a little bit of a phoenix will rise from those ashes.

(http://i735.photobucket.com/albums/ww356/VictorWilkens/IMG_1933_zpssexupey5.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/DSC_9396_zpsvantafsc.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/DSC_9401_zpsjck7vy49.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/DSC_9397_zpsyqshwuxf.jpg)
(http://i735.photobucket.com/albums/ww356/VictorWilkens/DSC_9399_zpsopycqscf.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Jan 08, 2016, 13:19:51
Looking good
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jan 08, 2016, 13:34:13
Glad it's coming back together Doc.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jan 08, 2016, 15:00:02
Helluva ride, Doc. 
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 10, 2016, 05:00:36
Thanks! Chipping away slowly.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 25, 2016, 03:04:16
The project bikes are back in storage for a few months but i kept a couple parts for to me to work on until I get a garage again. The lathe that i have access to just got rebuilt so i thought id finally machine a couple simple things on this to get started, as my skills progress I will attempt some more complicated stuff. I remade one of the front wheel spacers out of 7075, waiting on some stock to make a speedo plug for the LH side.

 (http://i1043.photobucket.com/albums/b436/doctorot/DSC_9463_zpskdvtming.jpg)

 I also turned a starter plug for the case; because the starter motor leaves this big gap on the front of the motor I really want to  put an oil cooler there, so I drilled and tapped two holes on the outside of the plug to help with the cooler mounting down the road.

(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9461_zps8k6asxca.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9462_zpscjn4czmn.jpg)


 I cut off the factory gauge mounts and polished it out.

(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9465_zpsipp5henn.jpg)

I got a Speedhut GPS speedo and tach. Nothin fancy on the gauge face but i but for about $20 extra they will give you a template and they will print whatever you want on a gauge face, so I designed my own.

(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9473_zps4n2tncld.jpg)

Im thinking about turning up a cover for the back of the gauge and want to try cutting threads in a tube. Do the machinists out there know what kind of thread this is or any tips on cutting ID threads?

(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9467_zps7ggbo4im.jpg)

 Im gonna use this 63-74 sportster headlight with a custom composite bucket that i originally made for my 1000 project. I am kinda digging the old school diffuser but if i go HID or LED i will use the clear lens. I think the screws at the bottom of the rings are kinda crude. Any suggestions to make it looks a bit cooler? I was thinking about some type of clamp or something.

(http://i735.photobucket.com/albums/ww356/VictorWilkens/moto3_zpse14f2d1e.jpg)

I just mocked it up real quick so i can start brainstorming ideas on how i want to tie this all together.

(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9471_zpsbsbpt9ov.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9470_zps3lza4jzb.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/DSC_9469_zpsieyh2acr.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 03, 2016, 03:06:09
Just a quick update, I finally had a chance to hop on the lathe and turn up the speedo delete. In just these two small parts i shaved almost half a pound from the front end. I'm really enjoying messing around on the machines. I picked up a tool blank to grind into the profile for the buttress thread on the tach/speedo. I practiced on some brass and think i have the thread cutting thing figured out well enough to attempt the internal thread.
Title: Re: saving a 1980 KZ750 twin
Post by: Signal on Feb 03, 2016, 03:54:49
Joined this forum in 2013, frequent visitor, this is my second post.
I really like what you are doing with this bike and how you are going about it, thank you for posting.
Hope you get some more machine time soon.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Feb 03, 2016, 12:20:45
If you spin up an extra speedo delete or tach plug, let me know.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 11, 2016, 07:46:31
Started working on the headlight ears by machining up these bits and welding em up. I made a sleeve out of aluminum to keep the tubes from going out of round while welding. now it's clear should have used steel for the sleeve because its stuck in the second. I'm going to slit them tomorrow on the mill and will cut through the sleeve too, hopefully that will help me get the sleeve out.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Feb 11, 2016, 08:25:48
The Eastwing only made it tighter. Weld a thick plug to the end with waffle marks and drive it out with a wood dowel from the inside, I would go into why but it just is always better to extract press fit aluminum rather than push it.

For the same reason I always tap the inside of valve guides, thread a bolt in and press the bolt surface to extract them... never galls the head or leaves aluminum on the guide  ;)
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Feb 11, 2016, 08:50:05
Yup.  The aluminum mushrooms easily.  CRC freeze off might help too. Shrink the aluminum to get it out.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 12, 2016, 04:58:34
thanks for the tips guys, that was a dumbass move on my part hammering the end. I ended up welding the end up like a coil pot to try and help shrink it down. the sleeve came out with some pounding, after slitting, but it galled some parts of the tube. I dressed it up and they mount great. Never done a slitting operation on the mill before. VERY satisfying. Now that these are finished I can start doing some prototyping.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 12, 2016, 20:39:11
 something like this.
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Feb 12, 2016, 20:47:00
Very nice stuff.
Title: Re: saving a 1980 KZ750 twin
Post by: redwillissuperman on Feb 12, 2016, 22:12:10
It's your bike but.... why the ginormous turn signals?


Sent from my iPhone using Tapatalk
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Feb 13, 2016, 05:50:30
It's your bike but.... why the ginormous turn signals?


Ha, I was thinking the signals and headlight looked kinda small-ish.   8)  But good.

BTW, do you got a link for those signals?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 13, 2016, 06:42:30
To each their own I guess. Both the headlight and turn signals are much smaller than stock. the wide angle lense on my phone is making them look bigger than they are. Trek - they are the bullet turn signals that air tech sells.  I think they have a good vintage vibe while still being small, this is my third bike with them. Unfortunately they only come in single filament but I have tracked down some parts to make them dual filament for running lights.  http://airtech-streamlining.com/miscpages/lights.html  EDIT- looks like dime city sells them now too.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 13, 2016, 06:44:12
Also I don't know why the pictures keep being sideways, they look normal on my phone
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Feb 13, 2016, 09:24:55
Also I don't know why the pictures keep being sideways, they look normal on my phone

load them to pc and correct them if needed. Your phone will auto rotate if you take it sideways or crop it
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 14, 2016, 05:56:52
the only bummer about doing the tach/headlight combo is there is no logical place to put this oil light. any suggestions?
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Feb 14, 2016, 19:24:50
Can it be displayed/programmed into that speedo?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 14, 2016, 21:55:20
The gauge has 3 idiot lights but they are all pretty small. If this oil light is coming on I want to notice it right away. I was thinking it might be possible to have the gauge back light flash or something but I have no clue on how to do that.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 16, 2016, 03:38:16
I ground the tool for the buttress thread and went for it. I remeasured the threads and it was 10 tpi. The threads didn't come out perfect but they very snugly grip the gauge so i'm calling it a success.
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2007_zpshqsqepdg.jpg)

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2012_zpsc1lt3krn.jpg)

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2011_zpslyqam1ev.jpg)

I have been doing some brainstorming on the solution for the oil light. I figured since the tach is integrated into headlight why not integrate the oil light into the inside of the left fork ear? it might look stupid once i mock it up, but i'm entertaining any possible idea right now.

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2013_zpssvaxbyay.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Feb 16, 2016, 19:44:50
Damn, with sketch skills like that I take it you're an Industrial Designer?  Looking good!
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Feb 16, 2016, 19:55:39
If my memory serves me right, those fork legs had a rubber cap that fit the square insets, maybe mount the light in one and the neutral in the other with some real small ABS tubes for wires tight on the back side out of view?

The art is damn nice too by the way. I would shed a few dollars for a good Foose style of some of my bikes??
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 17, 2016, 01:45:11
Damn, with sketch skills like that I take it you're an Industrial Designer?  Looking good!
yes. also currently pursuing a MFA in ID as well, hence the access to tools I can't afford.


If my memory serves me right, those fork legs had a rubber cap that fit the square insets, maybe mount the light in one and the neutral in the other with some real small ABS tubes for wires tight on the back side out of view?

The art is damn nice too by the way. I would shed a few dollars for a good Foose style of some of my bikes??

Yeah I thought about the fork tube cap but the light is so big it would have to stick up pretty high and look weird.
Unfortunately in-between work, school, and my own projects I hardly have time for anything else. If your not in a rush I might be able to make something happen this summer.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 17, 2016, 01:57:11
Had a little down time today so I re did the gauge housing. The threads are much nicer this time. You can see the one on the right has less chatter in the thread. I also added a little lip that I will leave polished with the rest painted. As much as I would like to use this headlight I think it is throwing the proportions off so in gonna look for one a little bigger, like a 6.25"
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 25, 2016, 23:39:49
I picked up this 6.25" headlight. I think the proportions are much nicer now.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 26, 2016, 22:06:16
Got a start roughing out the footpeg brackets today
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Feb 26, 2016, 22:47:55
http://www.ebay.com/itm/NOS-Honda-CB750-Cafe-Racer-Shelby-Dowd-Wheel-Set-CB-750-Lester-Henry-Abe-/301878429657?hash=item46495b47d9:g:KEgAAOSwk5FUyFyX

(http://i.ebayimg.com/images/g/KEgAAOSwk5FUyFyX/s-l1600.jpg)

 :o
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 28, 2016, 23:14:35
Got some more work in on the footpeg brackets. I screwed up and mis-calculated the chamfer on the folding boss and cut too deep. So I fired up the tig and put a dab on there and filed it back down. It looks ok. It's on the bottom so you won't see it when it's mounted.  Still a ways to go. I have no real clue what I'm doing so the going is slow.
Title: Re: saving a 1980 KZ750 twin
Post by: o1marc on Feb 28, 2016, 23:48:04
the only bummer about doing the tach/headlight combo is there is no logical place to put this oil light. any suggestions?
Drill a hole through the stem cap nut and mount it there.

(http://i253.photobucket.com/albums/hh79/o1racing03/Creative%20Candy%20Album%20II/Creative%20Candy%203/Triumph-KawaTon/cap%20nut%20light.jpg) (http://s253.photobucket.com/user/o1racing03/media/Creative%20Candy%20Album%20II/Creative%20Candy%203/Triumph-KawaTon/cap%20nut%20light.jpg.html)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 29, 2016, 01:55:27
Now that is a great idea. I will take a look at that. How much material do you think I can safely remove from the bolt with out compromising it?
Title: Re: saving a 1980 KZ750 twin
Post by: o1marc on Mar 01, 2016, 02:05:58
Now that is a great idea. I will take a look at that. How much material do you think I can safely remove from the bolt with out compromising it?
What bolt? The stem is hollow and has a cap nut on top. Drill a hole in the cap nut and run the wires out the bottom of the stem. You could cut the whole top of the nut off without compromising it's operation.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Mar 01, 2016, 08:02:51
What bolt? The stem is hollow and has a cap nut on top. Drill a hole in the cap nut and run the wires out the bottom of the stem. You could cut the whole top of the nut off without compromising it's operation.
These KZs have a bolt instead of a nut.  The inside of the stem is threaded, then the bolt tightens down with a thick washer.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Mar 01, 2016, 08:19:39
These KZs have a bolt instead of a nut.  The inside of the stem is threaded, then the bolt tightens down with a thick washer.

Small wires big bolt? drill through it and counter sink the light in the cap as shown.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 03, 2016, 00:19:10
The school/work combo has been kicking my ass and I haven't gotten any time in on the projects. I needed an easy win so I did sneak a little time on the lathe and made the tach plug.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Apr 03, 2016, 06:25:10
Very nice!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 07, 2016, 01:51:25
Finally got a start on the stainless header. Exhaust flanges next
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 07, 2016, 08:40:29
Spigots. You could sell those for a nice price you know... Make them for 70's Kaw and Honda
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 07, 2016, 17:18:46
Id have to try harder at sourcing some appropriate tube for that. I couldn't find any stainless tube that met the ID and OD requirements so I turned these out of a solid chunk of 2" 304. It took FOREVER.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 07, 2016, 17:37:43
And likely why they don't exist in our world, no cost effective materials. I want four when you find it for KZ1000
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 07, 2016, 17:47:24
I forgot I had these lol

(http://uploads.tapatalk-cdn.com/20160407/c595a40da26b633f7ba75373d6d922f1.jpg)

(http://uploads.tapatalk-cdn.com/20160407/172b65b9de2d4bc7c8b878def4f9645d.jpg)


Sent from my iPhone using DO THE TON (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=89466)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 07, 2016, 18:49:12
Those look nice.

Im planning out my header design and want to run over it here for my own clarity and to get the opinions of some knowledgeable folks here.
Its going to be a stock motor with the stock carbs and airbox. (for the time being)

The stock header ID is 1.28" Since i figure this is probably the optimal size for good velocity I didn't want to go bigger but the tube i have found comes in 1.5" with a .065 wall which puts me at 1.37" ID this is only 0.1" diameter increase so it shouldn't effect it much but will probably move the powerband up slightly in the RPM range.

From what I understand it is good to have a larger exhaust diameter than exhaust port to create a step to help prevent reversion. The exhaust port is 1.37". I don't want to go bigger because it would kill the exhaust velocity, so i have been scheming on ways to help prevent reversion. I put a internal chamfer on my spigots to mimic the factory header design where the two tubes are welded together. I figure a small step like this may help with reversion. 
I have also been reading about anti-reversion inserts and am contemplating adding them. Does anyone have any experience with them? i have read about them over at the XS650 forums and a guy that races one swears by them. Apparently they don't significantly increase power but help with throttle response and torque.
Im asking this because it will change how I design the exhaust flanges. If i do the anti-reversion inserts the exhaust collar will have to fit on from the head side and use a ring to hold the exhaust in place much like the factory. If i don't use the AR inserts the collars will simply slide on from the collector end. I drew up a cutaway real quick to show what I mean.

Thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 16, 2016, 02:19:45
Got a start on the exhaust collars.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Apr 16, 2016, 07:26:11
Man, cant believe you machined those exhaust flanges from billet stainless.  That shows extreme patience and dedication!  They look wicked.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 16, 2016, 15:28:27
Man, cant believe you machined those exhaust flanges from billet stainless.  That shows extreme patience and dedication!  They look wicked.

You can't believe it because its actually aluminum. I might be stupid, but not crazy enough to do this in stainless.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 17, 2016, 00:03:58
Got the retaining rings turnt
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 17, 2016, 09:20:10
Nice detail Doc
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Apr 19, 2016, 11:54:25
You can't believe it because its actually aluminum. I might be stupid, but not crazy enough to do this in stainless.

Aha, the spigots I meant.  Even so, dedication to the craft.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 19, 2016, 13:47:55
thanks guys
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 23, 2016, 22:56:29
Exhaust flanges are nearly done. Had some fun on the rotary vise, also thinned them a bit and sank the retaining ring a bit deeper. No chamfer mills so I chamfered them with files. They still need a bit of polishing.
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Apr 24, 2016, 18:04:11
Wow,very very nice.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 24, 2016, 19:43:28
Lucky dowg  >:(  Change the studs now they look nasty with the freshness
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 25, 2016, 04:53:29
thanks fellas. this is just a junk head to test fitment, I'm planning on using some stainless cap screws :D
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 25, 2016, 08:21:00
These are what I buy for headers mm8 12 points... the machined head is freakishly similar to your flange

4 for $12.** just what the Doc tor ordered  :o
http://www.ebay.com/itm/261499124624

Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Apr 25, 2016, 09:03:10
These are what I buy for headers mm8 12 points... the machined head is freakishly similar to your flange

4 for $12.** just what the Doc tor ordered  :o
http://www.ebay.com/itm/261499124624
Kinda funny when sales people talk about ti, highest grade means most brittle-hard iirc? From what i recall a scale of 1-8 where 8 is the hardest ti alloy. Oh well, no normal people ever think about these things so why should i, a mere lowly welder be concerned with it?
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Apr 25, 2016, 09:25:18
Kinda funny when sales people talk about ti, highest grade means most brittle-hard iirc? From what i recall a scale of 1-8 where 8 is the hardest ti alloy. Oh well, no normal people ever think about these things so why should i, a mere lowly welder be concerned with it?

Nah... Shit does seize up in aluminum so you do need to use the supplied anti seize 
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Apr 25, 2016, 09:28:55
Nah... Shit does seize up in aluminum so you do need to use the supplied anti seize
Thats why i like using studs and nuts in that particular application! Was talking about ti alloy grades though.. :)
exhaust flanges on my old trumpet i just glued on with hi temp jb 😂 will see how long that holds up, nothing like these sweet bits i reckon.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 06, 2016, 01:00:59
I started the footpeg brackets over. I want to check fitment before I proceed further. I'm no machinist, and a lot of eye balling was going on here, so these are less than perfect, but when I brush them I will remove inconsistencies and they will look pretty good
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on May 06, 2016, 08:38:34
Keep rockin Doc... But hurry, I'm gonna catch you  ::)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 06, 2016, 11:40:32
Shit I didn't realize it was a race :P more of a tortoise guy anyway.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on May 23, 2016, 18:31:43
Sweet Jesus. I finally start work on my KZ750twin and find all of these fantastic build threads.  Mine's just returning to stock (so far) but holy hell have you done some killer work man.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 24, 2016, 21:31:27
Thank you. Just having fun learning some new techniques and tools. I talked my buddy into letting me use his shop for a few months which means progress will continue very soon.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on May 25, 2016, 12:31:06
Rock on. You have certainly learned quite a bit and you are quite proficient at it! Keep it up!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 26, 2016, 20:42:57
Got the bike into my friends shop and he was nice enough to make me a key so I can come and go as I please. What a guy! I made a list of materials and parts I need to buy and should start fabrication on the headers next week. My buddy has a "rose bud" torch so I'm going to give the sand filled tube bending a try, a-la-Yoshimura. I'll attempt it in mild steel first and if that goes well I will try it in stainless. I mocked it up with some tube he had laying around. I don't think they'll be quite as swoopy as this.
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2350_zpsfxesjdod.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2349_zpsy7ihasvw.jpg)

https://www.youtube.com/watch?v=v8mMQbEkr8w
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on May 27, 2016, 01:43:59
Looks like fun and alot of gas.  I watched alot of that video.  That space he does that in is crazy.  All that flammable stuff.  Crazy.   Go for it Doc.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on May 31, 2016, 21:42:32
That's incredible. And yeah, I would have burned that place down before I got through that one pipe. Your turn Doc!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 16, 2016, 05:45:53
I posted this elsewhere on this site. if you didnt see it; i got distracted for 12 days, I had the opportunity to do an impromptu back-country hike in the Sawtooth Wilderness, so I rode out there and took the long way back. There were a lot of thunderstorms and even rode through some hail. Most of these photos are in Idaho and Central Oregon. I camped in national forests along the way, dirt-bagging it. good times.

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2532_zps6x5f8gq7.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2527_zpsvekzdmgo.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2516_zpsjvvzli8f.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2513_zpsos60ho2k.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2497_zpsfntktkn9.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2459_zpsf4qjp63y.jpg)

since getting back i have managed to get some work in on the bike. I made the plates for the close tolerance motor mounts and I chamfered them to match the exhaust collars. I also fit the ring I turned for the tach in the headlight bucket, sand blasted the ring and the bucket, and glued it in with some JB weld.

I finally got everything setup to do some sand bending. I already had some 1.5" tube with .095 wall so i tried it with that. for the final i will use 1.5" .065 wall. I don't know how much of a difference there will be in bending them with heat. The smaller kinked radius was the first attempt, the second attempt got a little crushed as well but it was a big improvement. The sand I used was damp when i packed it in there (there were vent holes) and im wondering if that perhaps the loss of water mass as vapour (which there was quite of bit of) allowed the sand to be looser. I'm also going to try welding a nut on the ends and using some all-thread to form a "packer" once it is welded shut. gonna give it another go this weekend hopefully.

any suggestions?

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2616_zpsxfwgg2m0.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2617_zpscpl4kfza.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2618_zpsyhvddgxg.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2615_zpslip7qv1l.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_2612_zpsttmn5fis.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jun 16, 2016, 07:42:04
In ceramics, typical shrinkage is 6 - 8% because of loss of water (another 7 - 10% during firing). It certainly would happen here.  In similar applications, I kiln dry the sand.  It also helps to get sand with variable grain sizes, as they tend to "fit" better together.  I don't think you'll need to go through that much effort, but food for thought.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Jun 16, 2016, 15:05:34
wow. That is all.


And seeing your priller makes me miss my RSV :( 
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 16, 2016, 16:45:06
Road trips like that are good for the soul Doc.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 16, 2016, 17:29:17
I will try drying the sand in the powder oven. I got impatient and just wanted to try it out. I think ill also get thinner tube because it will take less heat input to bend it.

I have another road trip planned for august. A friend of mine and his father are bringing their homemade twin engine triumph land speed racer to Bonneville this year all the way from New Zealand. I have wanted to go to speed week for a while now so i'm using this as an excuse to drive down there and meet up with them. Gonna take 3 weeks and do it right.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 16, 2016, 23:30:34
I will try drying the sand in the powder oven. I got impatient and just wanted to try it out. I think ill also get thinner tube because it will take less heat input to bend it.

I have another road trip planned for august. A friend of mine and his father are bringing their homemade twin engine triumph land speed racer to Bonneville this year all the way from New Zealand. I have wanted to go to speed week for a while now so i'm using this as an excuse to drive down there and meet up with them. Gonna take 3 weeks and do it right.


Hell of a good reason for a vacation.  I've always wanted to see Bonneville. 
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 25, 2016, 00:43:30
I got some 1.5" .065" wall tube. With the dry sand I could pack it much better. This was the second attempt but I ran out of O2. I think with a bit more practice I can get it pretty nice. The tight radius only crushed .17" I'm gonna try heating it a bit differently next time and see what happens.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Jun 25, 2016, 07:37:05
Ever watched the Yoshimura video bending pipe with no sand just perfect heat application?

https://www.youtube.com/watch?v=v8mMQbEkr8w
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 25, 2016, 17:39:41
I posted that video a couple weeks ago on here, and have watched it at least a dozen times. He definitely has something in the tube, you can see it sticking out at the beginning. I don't think its possible to bend a tube without it kinking unless you have some kind of support, either external or internal.
Title: Re: saving a 1980 KZ750 twin
Post by: Nebr_Rex on Jun 25, 2016, 18:37:31
All the good tube benders, i.e. expensive, have a mandrel.
I used to work at a steam boiler manufacture that bent their own tubes.
The Pines bender they had would bend a 2 in. tube with .105 wall at an 8 in. radius.


.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 25, 2016, 19:26:38
i really would love to use a CNC bender. I have 8 feet of mild tube left and 3 feet of stainless, if i dont get satisfactory results after going through all that, im gonna buy some stainless mandrell bends and make this the conventional way, just for the sake of "gettiner done"

https://www.youtube.com/watch?v=ot0Cxmk2aa4
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 27, 2016, 07:22:07
The mounts on the headlight bucket weren't parallel, and for some reason this bugged the crap out of me so I jb welded some washers in, and used some all-thread as a jig. I coated the all-thread and nuts in grease so I could go nuts (pun intended) with the jb weld and still remove the rod and nuts.

I got on to finally finishing the fork ears after turning all the parts months ago.

I was using a Miller Syncro wave and found it hard to dial the machine and the tungsten/air combo in to weld aluminum. My Chinese inverter welder zaps aluminum so easily with bright shiny welds, I always wondered why people said aluminum was hard to weld until I used the syncro wave. It was a great learning experience though. Eric showed me a bunch of tricks or welding aluminum and feel much more confidant even though most of the welds arent very cosmetically appealing.

It took me a solid 4 hours to grind and polish the welds down but I am pleased with the result. I decided to rubber mount the headlight since I have an expensive tach riding in it and don't want it to rattle itself to death. The turn-signal stems are too short now and I will need to turn some longer ones. it never ends.
Title: Re: saving a 1980 KZ750 twin
Post by: JustinLonghorn on Jun 27, 2016, 08:31:12
yep. Nice work.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Jun 27, 2016, 10:24:29
Yeah man. That's just right.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jun 27, 2016, 11:11:03
Really nice!  Will you need a third mount for the shell to keep it in position?  Looks like it could rotate in those nice bushings - especially now that they are nice and coaxial!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 27, 2016, 16:32:25
thanks guys.

I don't think a third mount will be necessary. the aluminum sleeve inside the rubber bushing is a little shorter so when the bolts are tightened it compresses the rubber pretty tightly. if it does move around i will address it later.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Jun 27, 2016, 18:51:42
Looking awesome man  8)

Those headlight brackets are craft.

Curious, what was this Chinese inverter welder that could do nice aluminium welds?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 27, 2016, 21:16:44
It's an Eastwood TIG. The synchro wave can get real nice welds as well it just needs the perfect setup. The inverters seem more forgiving
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 27, 2016, 23:39:41
I'd only guess on the hours for those ears but they are worth it.  Very nice.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Jun 28, 2016, 11:59:58
Ole yoshi probably taught his guys to bend with a spring inside.  Does the same trick as sand.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 28, 2016, 22:18:19
Ole yoshi probably taught his guys to bend with a spring inside.  Does the same trick as sand.
now thats an interesting idea. i wonder were i could get a spring that would be the right size.
Title: Re: saving a 1980 KZ750 twin
Post by: hillsy on Jun 29, 2016, 00:25:33
now thats an interesting idea. i wonder were i could get a spring that would be the right size.


Fork spring? Sure would be strong enough.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Jun 29, 2016, 04:06:54

Fork spring? Sure would be strong enough.
And plentiful of different diameters at the breakers!👍I've never done it myself, but as a pipefitter welder i pick up a few things from the old boys..
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 29, 2016, 12:17:30
Sounds interesting getting the spring out of the pipe after bending..
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jun 29, 2016, 12:36:27
Sounds interesting getting the spring out of the pipe after bending..

Right!  I've tried that long ago with much smaller tubing - both inside and outside but no heat.  Total failure.  I'd expect an internal spring to lose all its support strength heating the tubing sufficiently, and be impossible to remove, but it is just a guess.  I would expect the bending to seriously clamp the spring, and then contracting when cool to make it a permanent assembly!  Sand,compacting, caps, and heat definitely works though, but you need a seriously big torch!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 29, 2016, 17:21:11
Ill bring my good camera with me the next time I try and and get a video.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 03, 2016, 06:51:38
I'm wondering if need to face reality and just give up with the sand bending. Ive gotten better, but the small radius still crushes. It is thinning down to 1.37" diameter from 1.5". I doubt this would have much of an impact on the exhaust performance, but I just don't like the way a crushed tube looks.

Thing I have learned;
>Thinner tube does not crush easier than heavier tube
>set the torch to a  high reducing flame (more fuel than O2) to get a nice even heat on the tube.(use A LOT of gas)
>use as little as heat as possible, heat till red NOT orange.
>use dry sand (duh)
>taping the tube on the ground  and welding on sheets to cap the ends is just as good as welding a nut and rods on to the ends to "pack" the tube
>heat the area you want to bend and extra 4" on either side.

This is something I could chase for a long time and spend a lot of money on materials. I think it may be time to cut my losses and buy some mandrel bends. At the very least buy the small radius curve and sand bend the rest. This is the best result i had. I also found that because of the frame clearance i had to use studs and acorn nuts to secure the flanges.
Thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jul 03, 2016, 08:30:37
Thing is Doc, a mandrel can be cinched as well.  You have to make sure you get full diameter bends. 

(http://www.punishment-racing.com/product_images/uploaded_images/crush-bend.jpg)

Kits like what TC Bros sells are not full diameter.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jul 03, 2016, 10:48:36
I think your pipe looks great in the pics, though I can see noticing any lack of uniformity being a lot more obvious in person.  You may have the right idea combining manufactured bends and torch bent sections.  Personally I like the more organic look of the hand bent pipes but if you can't make the tight radius portions acceptably than grafting in a pre bent piece for that portion would seem to be a way to get the best of both worlds.  Deviant, your pic is not a drawn over mandrel tube.  In the main, a mandrel is an internal die like a round ball on the end of a long pole that is kept located inside the tube where the forming operation is happening, but the term mandrel is often used for all sorts of fixtures including outside parts so there is some ambiguity.  Proper mandrel bent tubes have perfectly round sections and are indistinguishable to the eye from the straight tube.  Here is a 2 1/4" dia stainless steel tube with a very tight bend.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jul 03, 2016, 10:54:28
I think your pipe looks great in the pics, though I can see noticing any lack of uniformity being a lot more obvious in person.  You may have the right idea combining manufactured bends and torch bent sections.  Personally I like the more organic look of the hand bent pipes but if you can't make the tight radius portions acceptably than grafting in a pre bent piece for that portion would seem to be a way to get the best of both worlds.  Deviant, your pic is not a drawn over mandrel tube.  In the main, a mandrel is an internal die like a round ball on the end of a long pole that is kept located inside the tube where the forming operation is happening, but the term mandrel is often used for all sorts of fixtures including outside parts so there is some ambiguity.  Proper mandrel bent tubes have perfectly round sections and are indistinguishable to the eye from the straight tube.  Here is a 2 1/4" dia stainless steel tube with a very tight bend.
THat's why I said he needs to get full diameter bends.  Here's a drawing of the process.  My point in bringing it up, is the process is usually a custom process and off-the-shelf  full diameter kits are typically not offered.  The majority of local shops don't offer it either. We always run full diameter pipes on our drag cars. 

(http://www.bendtooling.com/RDTBG-Fig-2.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jul 03, 2016, 11:05:08
Cool drawing!  Pics worth a thousand words!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 03, 2016, 17:59:24
I was gonna buy the bends from Burns stainless, which is where that pic is from i believe. I'm gonna order the slip for the muffler as well. I did the math and double the internal volume of a 1.5" tube is a hair over 2" tube, so I'll go with 2.125" tube for the collector.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jul 03, 2016, 20:31:13
how about that!  I found that pic at random from a quick search - had no idea where it came from!
Title: Re: saving a 1980 KZ750 twin
Post by: teazer on Jul 03, 2016, 21:10:10
Check with Megs/Cone engineering.  According to a table I downloaded a while ago, 2 into 1 collectors require an outlet of 150 to 175% area of the primary pipes.  That works out to 1.875 to 2" and use the smaller size for a more torquey motor.
Title: Re: saving a 1980 KZ750 twin
Post by: clem on Jul 03, 2016, 23:17:15
When I worked offshore in the instrumentation world the majority of what I did when I started out was bending tubing for process and utility connections. We did mainly from 1/8th inch up to 1-1/4 inch stainless 316, 317L, monel,  inconel, 2507...Thousands of feet and the bender makes all the difference. You need a shoe with the diameter desired that is rounded out to hold the tube then a shoe to pass around the outside with the same diameter as the tube, rollers on the outside give the best bend without flattening. Most benders that I've used without rollers on the shoe flatten the tube to some degree. With all of that nonsense I just laid out you're on the right track with just buying pre-bent pieces. It'll be less headache since you don't have access to a bender.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app (http://'https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=89466')

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 04, 2016, 00:12:56
Check with Megs/Cone engineering.  According to a table I downloaded a while ago, 2 into 1 collectors require an outlet of 150 to 175% area of the primary pipes.  That works out to 1.875 to 2" and use the smaller size for a more torquey motor.
yeah i wondered if that would be too big. Ill drop down to 2" and buy one of the pre-made collectors from cone engineering.
Title: Re: saving a 1980 KZ750 twin
Post by: Rider52 on Jul 04, 2016, 02:04:24
Back in the early 80's I built a scrambler type 2n1 exhaust system for a Kaw 750 twin. I used mandrel bent and straight pieces from Summit.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Jul 04, 2016, 04:38:44
Right!  I've tried that long ago with much smaller tubing - both inside and outside but no heat.  Total failure.  I'd expect an internal spring to lose all its support strength heating the tubing sufficiently, and be impossible to remove, but it is just a guess.  I would expect the bending to seriously clamp the spring, and then contracting when cool to make it a permanent assembly!  Sand,compacting, caps, and heat definitely works though, but you need a seriously big torch!
U waz prob holdin it wrongz😁
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Jul 04, 2016, 04:41:15
When I worked offshore in the instrumentation world the majority of what I did when I started out was bending tubing for process and utility connections. We did mainly from 1/8th inch up to 1-1/4 inch stainless 316, 317L, monel,  inconel, 2507...Thousands of feet and the bender makes all the difference. You need a shoe with the diameter desired that is rounded out to hold the tube then a shoe to pass around the outside with the same diameter as the tube, rollers on the outside give the best bend without flattening. Most benders that I've used without rollers on the shoe flatten the tube to some degree. With all of that nonsense I just laid out you're on the right track with just buying pre-bent pieces. It'll be less headache since you don't have access to a bender.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app (http://'https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=89466')
Yes those are the nicest, did a lot of stainless piping with hydraulic benders at the nuke plant last year. Lots of bends since they try to avoid unnecessary welding.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Jul 04, 2016, 08:30:34
Key to perfect mandrel bends is clean pipe inside and out and a well cared for wiper die, the balls and wiper need a puff or two of graphite every 10 or so bends. a cnc bender can bend a compound radius just not 100% continuous it needs to let go and rotate then re clamp several times. I bent many miles of 4" stainless for Dodge Cummins trucks and QC would not let a wrinkle go by.

I don't think Yosh is using anything inside the pipe, it's Ninja bending skill and heat  ::)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 04, 2016, 14:58:58
Back in the early 80's I built a scrambler type 2n1 exhaust system for a Kaw 750 twin. I used mandrel bent and straight pieces from Summit.

pics?
Title: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Jul 05, 2016, 10:19:23
Check with Megs/Cone engineering.  According to a table I downloaded a while ago, 2 into 1 collectors require an outlet of 150 to 175% area of the primary pipes.  That works out to 1.875 to 2" and use the smaller size for a more torquey motor.

I have a pair of these: if you need one!

(http://uploads.tapatalk-cdn.com/20160705/a991c92f0831603c996d8c8879ffc1ca.jpg)


Sent from my iPhone using DO THE TON (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=89466)
(http://uploads.tapatalk-cdn.com/20160705/0da22832f7ace2830a5117a92de91e09.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: VonYinzer on Jul 05, 2016, 12:27:31
I have a pair of these: if you need one!

(http://uploads.tapatalk-cdn.com/20160705/a991c92f0831603c996d8c8879ffc1ca.jpg)


Sent from my iPhone using DO THE TON (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=89466)
(http://uploads.tapatalk-cdn.com/20160705/0da22832f7ace2830a5117a92de91e09.jpg)

What are the inlet/outlet sizes there Fish?
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Jul 05, 2016, 14:57:09
1.5 and 1.75 apx, i will put a measuring device onem and see for certain
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 18, 2016, 01:36:27
I ordered some bends from Cone Engineering and was kinda disappointed in the quality. Not much better than my crushed sand bent radius. and they had creases on the outside of the bend. The first bend of the header is very visible so I bought some bends from Colombia Mandrel and the quality was much nicer and 7 bucks cheaper a piece to boot!

My buddy Eric thought 2" would be too big for the collector so I dropped that down to 1.875". This meant there were no cheap collectors to be bought so i had a go at making my own.

I hammered open the ends of the primaries and then faced them on the disk sander before welding them together to try and keep stress out of the welds. It still took a good amount of bashing after to get it to fit up.I also ovaled the big tube slightly to help out the transition. I was super shaky welding this up for some reason so the welds arent my best, I probably should have done some practice beads first to get in the groove but you will never see these welds when the pipe is on the bike, so whatever. I also compressed the fork to make sure there would be plenty of clearance. next up is sand bending the second bends.
Title: Re: saving a 1980 KZ750 twin
Post by: WackoTie on Jul 18, 2016, 02:11:25
Looks great man

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Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Jul 18, 2016, 17:10:28
Nice work on the collector. I used a 2-1 collector from cone eng on the 360 headers and they neglected to tell me about the little triangle filler pieces. I ended up welding it to the headers once, removing it and rewarding between the two header pipes from the inside since it was impossible to fill the voids. I'll just make my own next time.


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Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 18, 2016, 22:27:41
Thanks guys
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 20, 2016, 03:22:01
Guess they were worried about vibrations.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 20, 2016, 12:03:14
Ya think?  Lol.   
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jul 20, 2016, 12:13:09
Very important for the battery!  (somewhat less so for some of the new tech batteries)  Be glad you have all the bits - some are a pain to find and put everything back proper!
Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Jul 20, 2016, 13:16:45
Guess they were worried about vibrations.

Try soaking those rubber bits in DOT3 brake fluid overnight. I had some pretty good results on the XL rubber parts. It doesn't make them look new but it gives them back some of their flexibility.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Jul 20, 2016, 14:43:08
good idea, but have a care.  Soaking any rubber parts in brake fluid (methyl salicylate (wintergreen oil) and acetone is better) can do wonders, but pretty easy to overdo, so keep a close eye on how long you soak.  Some parts can seem fairly immune, but some can expand and become ruined unexpectedly.  Methyl salicylate is better IMHO and does not eat paint like brake fluid.  Go cart guys use it to prep their tires so check out cart suppliers if you want some.  Can also be had at drug stores slightly altered and way more expensive but it still works.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 20, 2016, 16:53:39
I have used wintergreen oil on carb boots before and it works pretty good. Only the 4 bushings that hold the battery to the frame are in bad shape and they are still available from Kawasaki for a little over a dollar a piece. I looked up the bikes that use these bushings and its well over 100 models all the way to 2016. guess Kawasaki got their moneys worth out of those molds.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 29, 2016, 01:25:10
The 2.5" radius just looked a tad small so I got this 4" radius (from Burn's Stainless, best quality so far) for the first bend and I think it looks much better; and in theory it should flow better. I got my two bends done for the second part of the header. It was 92 degrees in the shop and after letting loose with the big torch the temp climbed to 105. I was listening to my sweat drip off and sizzle on the pipe, don't want to do that again. Thankfully sand bending is over at this point. Need to fit them up and weld it all together. Eric also picked up a powder coater he was keen to try out so we re-powdered the top triple.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 29, 2016, 04:22:10
can anyone point me to info on calculating primary and collector lengths?
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jul 29, 2016, 08:14:30
https://www.amazon.com/dp/0854292756/ref=olp_product_details?_encoding=UTF8&me=

and

https://www.amazon.com/dp/0837603099/ref=olp_product_details?_encoding=UTF8&me=
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Jul 29, 2016, 13:06:40
I like this guys info, tests and explanations.  Aaand, nice calculator:

http://www.mezporting.com/exhaust_length.html
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jul 29, 2016, 13:21:32
I like this guys info, tests and explanations.  Aaand, nice calculator:

http://www.mezporting.com/exhaust_length.html
He gets all that from the books I linked.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 29, 2016, 14:07:31
thanks guys
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 16, 2016, 04:07:16
I haven't been able to get any work on the project bikes because I have been rebuilding a 78 kz650 with a friend. thought it was gonna be a quick tuneup to get it on the road and it ended up needing damn near everything. We tore it down to the frame and rebuilt the top end of the motor and pretty much rebuilt or replaced everything else. Now that is done i'm hitting the road for a couple weeks on my Falco and when I get back I am going to have a "fabrication vacation" and stay at Eric's shop (50 miles away) for three days while we jam on the kz750 and the kz1000 project to get as much done as possible before I head back south to California for the year. I hope to finish the header for the 750 and bunch of small stuff for the 1000.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Aug 16, 2016, 09:06:15
Nice work horse, just the way it should be for a DR
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Aug 16, 2016, 16:13:42
Nice KZ650 for sure.   I wish I had time to build one of mine.

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 06, 2016, 15:45:44
Whelp, I finally pulled my finger out and finished the header. It came together pretty nice, but I did have to fudge the fitup a little bit where the second bend meets the straight. You can't see it when its on the bike and I doubt it will affect flow very much. Eric made this sweet tool for putting a uniform finish on headers and it worked great, started with 80 grit and then a polishing belt for a uniform brushed finish before welding it all together. My welds came out OK, still a bit too hot, I'm undecided if I want to polish the heat marks off or not. I also need to start thinking about what I want to do about the muffler, thinking about a kerker-esque stainless can for that vintage performance vibe.

https://www.youtube.com/watch?v=LNCrIJaAzoI

Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Sep 06, 2016, 15:57:53
Very nice finish mang!

How do I get one of those attachments tho... I have a small bench one and have used a crank polisher or bow sander but that is kewl mang!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 06, 2016, 16:51:08
Thanks Tune. Eric made the attachment. its two plates that bolt together to adjust the tension of the belt and he used a scooter wheel. I can probably get some better photos of it if you want.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Sep 06, 2016, 17:19:12
Damn Doc, those pipes look amazing.  Really nice work.  I don't have those skills but you sure do. 
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Sep 06, 2016, 17:36:08
Damn Doc, those pipes look amazing.  Really nice work.  I don't have those skills but you sure do.

Agreed! Those look fantastic.  Can't see anything wrong with them.  You did fantastic work!
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Sep 06, 2016, 17:50:05
Thanks Tune. Eric made the attachment. its two plates that bolt together to adjust the tension of the belt and he used a scooter wheel. I can probably get some better photos of it if you want.

I would give it shot, looks simple enough for even me to attempt
Title: Re: saving a 1980 KZ750 twin
Post by: semmins on Sep 06, 2016, 18:18:33
Really nice job with the down pipes.
I've used these scotch brite mops on stainless exhausts, a few times, and got half decent results.
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Sep 06, 2016, 18:27:11
If you turn the emery belts inside out you may be able to adapt a belt sander motor and tires to some frame I would like to have variable speed... the brain is in full gadget mode mang.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 06, 2016, 21:25:49
Thanks guys.
I finally had some time today to get settled into the new place. For the first time in 5 years I have my OWN garage. It is small but I am so pleased to have my own space. I took the time to wheel the bikes out and get some progress shots with the good camera. I got a bunch of small stuff done on the bike in the last month; painted the rotors, painted the wheel spacers, got the airbox and battery tray installed, got the headlight painted in sealer, and traded for some black Daytona bars. Time to start thinking about paint....
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Sep 07, 2016, 04:47:33
Congrats on owning a garage!  You won't know yourself.  That'll be a long way off for me.

The bike is looking amazing.  This is almost the look I am trying to achieve with my SR.
Title: Re: saving a 1980 KZ750 twin
Post by: semmins on Sep 07, 2016, 06:19:32
Just a thought, regarding paint....
Title: Re: saving a 1980 KZ750 twin
Post by: JustinLonghorn on Sep 07, 2016, 07:42:25
Looks damn good, man.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 07, 2016, 12:44:17
Just a thought, regarding paint....

great minds think alike! I was considering something like that, or a burgundy, or "jeep rescue green" I'm going to do some photoshop mock-ups for paint
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Sep 07, 2016, 16:17:46
Doc, that bike is fookin' sweet!  She's a looker now.  Something most wouldn't honestly say about the heavy kaw.

Excellent work for sure!!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 09, 2016, 05:43:01
Hopped on the lathe tonight and got the longer turn signal stems finished for the headlight. I also added a washer.

what to do about the paint... this is one thing I am having a hard time settling on. I would like to try and incorporate some white in it somewhere to tie in the grip rings and shocks. Right now I'm leaning more towards  the large white stripe on the bottom because I am planning on doing pinstripes on my 1000 and want them to be a little more different. i think most of these colors would look good with the white stripe. thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: Kamn on Sep 09, 2016, 08:05:49
I personally like C,D, and G
And for myslef I think I would do C
Title: Re: saving a 1980 KZ750 twin
Post by: jag767 on Sep 09, 2016, 08:14:07
C
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Sep 09, 2016, 08:36:34
Can you lay Renault Electric blue on one just for kicks 
 

Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Sep 09, 2016, 10:21:57
I'm no painter, so forgive the paint and how ugly mine is compared to yours, but here's mine :)
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Sep 09, 2016, 12:09:10
Oh man, totally personal preference but I think E.  The least 'look at me' of the bunch.  Nice and classic.
Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Sep 09, 2016, 12:11:43
C or D, any with the white stripe on the bottom. Tune may be onto something with the blue though... ::)
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Sep 09, 2016, 12:13:22
D tank, F sidecovers but with the 750 emblems too.. 
Title: Re: saving a 1980 KZ750 twin
Post by: semmins on Sep 09, 2016, 13:13:43
Tough choice.  Probably E, perhaps with light green, and gold pinstripes, or then again.....
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Sep 09, 2016, 20:25:30
C for my first, then G.
and Im sorry bro but you need to double check the direction arrow on that front tire mount.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 09, 2016, 21:26:03
C for my first, then G.
and Im sorry bro but you need to double check the direction arrow on that front tire mount.
damn, you can see the mounting arrow? its on there correctly tho.

well its looking like C is the winner here. I'm gonna wait on it a week or two and ponder it some more before I buy paint. I'm also thinking about the rescue green with the stripe treatment to be a bit different. My last KZ650 was "luminous blue" so I'd like to change it up a bit.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Sep 09, 2016, 21:30:55
damn, you can see the mounting arrow? its on there correctly tho.
He's going by the tread direction on the Roadrider tire, which is reversed for the front compared to the back.  They're a tire made to mount front or back, so the arrow printed on the side is a dual arrow and says front at one side and rear at the other.  Your front is mounted the same way as your rear in the pic. 
Title: Re: saving a 1980 KZ750 twin
Post by: jag767 on Sep 09, 2016, 21:52:49
Damn, that front tire does look like it's mounted backwards. I like that blue
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Sep 09, 2016, 21:53:05
Right - need to be sure the rotation is correct for front or back.  Most directional tires are different front or rear because of the internal construction.  Usually the tread pattern is not the reason.  It's important because the rear wheel gets all its loading when pushing the bike forward due to engine power.  The laminates inside the tire overlap at the ends and the manufacturer wants the load to not try to separate the laminates.  Think of it like a roll of masking tape.  Run your fingernail against the end of the tape going in the direction of how its wound and nothing happens.  Go against the winding direction and you will try to peel the tape back.  When you brake, the effect is reversed so the tire needs to go the other way round.  On the front, the big loads are only when braking.  On the rear, the braking load, while wrong for the tire construction, is pretty small compared to what the front sees or compared to the drive from the engine so you pick the lesser of evils and orient it accordingly.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 09, 2016, 21:54:44
feck, dont how i missed that one. good lookin out, add that to the list of crap to do.
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Sep 10, 2016, 08:18:17
I dont know why I have it in my head.  But the different makes have "theme" colors.
To me, Kawi = green, Yama = blue, Honda =red, Suzuki = yellow.
Its funny cause Im pretty darned color blind anyways.   ;)

But I can see the green you chose for PS mockup aint blue or yellow. and I prefer that.

Especially a red Suzuki or Yellow Yamaha just makes me cringe inside.  Especially on factory bikes.

I painted my  little CL Cub Cadet beige...it looks nice but even still it has yet to grow on me.   ::)

Bottom line...I like any Green you choose for your machine.

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 11, 2016, 18:11:42
I dont know why I have it in my head.  But the different makes have "theme" colors.
To me, Kawi = green, Yama = blue, Honda =red, Suzuki = yellow.
Its funny cause Im pretty darned color blind anyways.   ;)

But I can see the green you chose for PS mockup aint blue or yellow. and I prefer that.

Especially a red Suzuki or Yellow Yamaha just makes me cringe inside.  Especially on factory bikes.

I painted my  little CL Cub Cadet beige...it looks nice but even still it has yet to grow on me.   ::)

Bottom line...I like any Green you choose for your machine.


I have similar sentiments, which is why I am leaning towards the green.

The timing of noticing the tire was backwards couldnt have been better because I needed to change the rear tire on my falco so I went to Moto guild  in San Jose and for $15 I got to use their tire changer for an hour. Thanks for protecting myself from myself guys
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Sep 12, 2016, 07:31:30
(http://www.dotheton.com/gallery/11494-200816163635.png)
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Sep 12, 2016, 09:43:21
Nice mid green color the classic logo is sweet

(https://s-media-cache-ak0.pinimg.com/564x/91/a8/ca/91a8ca29e26ce4c9826ce455578007ee.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Sep 12, 2016, 16:41:23
Nice mid green color the classic logo is sweet

(https://s-media-cache-ak0.pinimg.com/564x/91/a8/ca/91a8ca29e26ce4c9826ce455578007ee.jpg)

Now that is sweet!  That logo is truly timeless I reckon.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 12, 2016, 22:23:51
I personally prefer the older style text. KAWASAKI instead of Kawasaki. I swapped engine covers for the older style
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Sep 13, 2016, 04:27:35
I personally prefer the older style text. KAWASAKI instead of Kawasaki. I swapped engine covers for the older style

Wow, they run two different versions of logo even in engine cases?  Thats cool.  Well you should run with the one you prefer of course.  Aren't most motorcycle brands/logos all in caps anyways?
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Sep 13, 2016, 10:04:43
I missed that too, I knew the two logo's but missed the cases... very nice Doc... Let the good times roll  :o
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 23, 2016, 02:07:00
When I was helping my buddy rebuild that kz650 this summer I donated the factory dual caliper setup I had slated for this build and bought some Brembo P108 calipers.
I'm doing this at the same time as the brakes on my 1000 to try and save some costs on waterjet cutting.

I needed spacers for the disks to allow clearance for the spokes. Really I'm just looking for any excuse to use the rotary table. god I love that thing.

I then drew up a bracket in CAD and laser cut the profile out of  .060" acrylic so I could stack them to get the correct spacing. I have the spacing pretty spot on but the bracket sticks out pretty far and will require removal of a lot of material when I mill the plate down. I'm contemplating milling some material off the inside of the caliper mounting bosses on the forks so that I will have space to mount the bracket on the inside of the forks and caliper which is a better solution IMO.

I'm not sure on how to approach milling material off the forks. I think I will first have to mill some material off the side (round part) of the bosses first so I can clamp the fork bottom in the vice securely. Should I indicate off the stanchion tube to ensure I am parallel to the the boss faces? Any tips here?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 28, 2016, 01:03:02
I threw the forks and triple trees on the mill and clamped the axle in the forks.  I then indicated off the axle so that the new caliper boss faces would be perpendicular to the wheel axis. I used paint stripper to remove the paint on the caliper bosses to make sure i was getting accurate readings off them to check against the axle readings. I took off 8mm, and now the mounting brackets can fit on the inside. I used a ball end mill so that the bottom of the cut would not be a stress raiser.

I finally rounded up the last bits for the carbs. NOS intake rubbers, new aftermarket carb boots, and a member over at KZR hooked me up with some trick billet mounts for the carb boots to replace the old plastic ones. I gave them the brushed treatment to match the motor mounts.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Sep 28, 2016, 03:15:16
Looking stunning man.  Smart using the ball end bit.  Had some simulations done recently on some plastic parts I designed and just adding a 0.5mm rad added an extra 25% strength in the critical areas. 

I really like that stock/modded intake set up.  Those triangular boot mounts are trick!
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Sep 28, 2016, 12:11:07
Doc, those intakes are slick. 
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 28, 2016, 13:46:03
thanks guys. the files are off to the water jet cutter today! Since I'm paying for the drops as well i decided to have them cut in a manner that i don't have to create a fixture to mill them. Once the mill operations are done I will cut off the excess with a band saw and then finish them.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 05, 2016, 15:26:19
Green won. Hopefully ill be able to prep everything and spray the test piece I have this weekend before committing fully
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Oct 05, 2016, 15:57:57
Doc, your front tire is mounted wrong for a front application, There are 2 rotation arrows one for front one for rear as that is a universal model Avon designed for either application, the way you have it mounted will direct water straight at your back tire and you increase hydroplaning risk by a lot and also effect cornering traction. Bike is looking good, I like the paint colour you chose.

edit, it looks like it is mounted right in the brake mockup pics, did you swap it around?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 05, 2016, 17:55:48
Thanks. The tire was brought to my attention and has been fixed.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 10, 2016, 00:49:10
everything is ready to rock and test is sprayed. I was hoping it would be a little more green but i do like the color. I might go buy some of the green toners and add a bit. I also pressure tested the gas tank in my sink to check for leaks before committing to paint. Hopefully this Friday it will go down  8)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 10, 2016, 15:36:52
It looks better in the sun
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Oct 11, 2016, 04:33:05
Looks niiiice.  Looks expensive actually.  Nice flake/sparkle/whatever it is in there  ;D
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 16, 2016, 19:38:57
I got the color where I want it. Its a tiny bit more gold than it looks in the photo. I was spraying this out last night and the gun spit out a huge fleck of crap right on the top left. so I'm going to sand it back and respray next weekend.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Oct 17, 2016, 11:43:56
Bummer on the huge fleck :(  But boy is this thing going to look awesome!!!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 17, 2016, 15:43:18
thanks. Its just part of the 2 step forward 1 step back shuffle that my projects seem to do.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Oct 17, 2016, 17:09:30
thanks. Its just part of the 2 step forward 1 step back shuffle that my projects seem to do.

We all have that happen.  At least you  know how to paint. I just have to drop the stuff off and swear at the bill when done.  8) :o
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 22, 2016, 19:32:39
Paint came out pretty good. Photos don't do the metalics in this justic, it really pops in the sun. Unfortunately they  sprung for the cheap filters on this spray booth and the fibers seem to find their way into the paint no matter how much I clean before hand, luckily when wetted by the clear they turn transparent so a little cut and buff and you will never know. I won't be able to get to striping this for a couple weeks.
Title: Re: saving a 1980 KZ750 twin
Post by: interceptor on Oct 23, 2016, 07:43:08
I enjoyed reading through your build.  Great job!  Looking forward to seeing the paint on the bike.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Oct 23, 2016, 08:47:42
Wow man.  Gorgeous.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 23, 2016, 16:14:15
thanks guys
Title: Re: saving a 1980 KZ750 twin
Post by: bradj on Oct 23, 2016, 16:37:15
I got a kz rear disc hub setup if your interested
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Oct 23, 2016, 19:02:14
Thanks but im  sticking with the drum. I think it looks awesome in the aluminum swingarm and has more than enough stopping power.
Title: Re: saving a 1980 KZ750 twin
Post by: trek97 on Oct 23, 2016, 20:02:05
Both the color and finish is beautiful dude.
Title: Re: saving a 1980 KZ750 twin
Post by: semmins on Oct 24, 2016, 17:06:00
Paint looks excellent.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 29, 2017, 03:30:23
I have been working on this ignition cover for several months off and on whenever I have a short downtime. They're finally finished. I based them off the badges on the early Kawasaki exports. I designed it in CAD and had it 3-d printed so I could take a rubber mold off of it and then cast it in wax. First time ever casting aluminum, which I poured myself, so no photos. I did get some photos of the bronze being poured. They came out ok, but the final casting was very rough and porous. Lots of filing and sanding later they look pretty good.....good enough for an ignition cover. I also made some bronze belt buckles from a mold I took off an KZ650 ignition cover.



(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3641_zpsc4vcdmn9.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3644_zps462m5pjy.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3877_zpshnz8dwk5.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3880_zpsc2gqae4r.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3883_zps7plt1ynh.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3621_zpslytotyqn.jpg)

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_0177_zpsdu16kgwv.jpg)
(http://i1043.photobucket.com/albums/b436/doctorot/IMG_0178_zpszj58ccja.jpg)


(http://i1043.photobucket.com/albums/b436/doctorot/8aa7d6ad-e94d-410f-9f1a-39736ae1de65_zpsw5cikdme.jpg)

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 29, 2017, 03:34:22
i like shiney
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Jan 29, 2017, 07:27:05
Whoa man, this is next level shit.  Really inspiring stuff!  They came out great :)
Title: Re: saving a 1980 KZ750 twin
Post by: pacomotorstuff on Jan 29, 2017, 08:46:58
Hi Doc,
Nice investment casting - the oldest casting method known to mankind and still a great way to make parts.  Something you learned in your day job (you're a dentist, right)?  I have a couple of places in my town that do it, but I've never approached them about doing some one-offs or small runs.
Neat 3D modelling - I should really get into it, but I'm from the old school of patternmaking (learned it 35+ years ago when I was working my way through school), where you make the master by hand on the bench, figure out the shrink allowance and adjust the pattern to suit.  Wow, how much easier would it be to push the button on the keyboard to make the pattern a little bigger and then CNC the master?
Looks like a pretty big riser for the part (a lot of metal left in it after chilling) - but too much is better than too little, right - and the foundry just remelts the offcuts anyway?  Also wondered why your foundry didn't suggest using a gating system and pour a number of parts at one time?
I gather it's A356 aluminum alloy - seems to be the bread and butter casting alloy in these parts and the finished product doesn't seem to exhibit any of the issues of a casting with a lot of reclaim in it?
BTW, the above are not criticisms, just questions - there are many, many ways to accomplish the task and... I was just curious.
Your attention to detail is awesome , incredible, inspirational - maybe just the thing to shake a lot of us out of our winter lethargy, up here in the frozen north.
Most excellent build.
Pat
Title: Re: saving a 1980 KZ750 twin
Post by: Nebr_Rex on Jan 29, 2017, 09:36:20
Would you consider casting up some more for sale?
The KZ400/440 use the same cover. :D


.
Title: Re: saving a 1980 KZ750 twin
Post by: Green199 on Jan 29, 2017, 09:43:19
God damn, this may be one of my favourite builds on this site. Love the fabrication work you've put in and the cast covers turned out very nice.

Looking forward to seeing a pic with the bodywork back on the bike, but damn, it looked good in satin black!  :-X
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on Jan 29, 2017, 10:01:09
Namaste  :o
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jan 29, 2017, 15:33:36
Outstanding work Doc!  They really came out nice.
Title: Re: saving a 1980 KZ750 twin
Post by: teazer on Jan 29, 2017, 17:17:49
Talk about raising the bar.  Nice work.  Color me impressed.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 29, 2017, 18:13:58
Thanks guys. Just having fun.


Hi Doc,
Nice investment casting - the oldest casting method known to mankind and still a great way to make parts.  Something you learned in your day job (you're a dentist, right)? 
Hahaha. I'm no dentist, or even a real doctor. just a nickname that stuck from highschool.

Wow, how much easier would it be to push the button on the keyboard to make the pattern a little bigger and then CNC the master?

Yeah it takes about 5 seconds to scale something in Rhino. Heres the 3-d printed master that I took a mold off of, and the original badge I based it off of.




Looks like a pretty big riser for the part (a lot of metal left in it after chilling) - but too much is better than too little, right - and the foundry just remelts the offcuts anyway?  Also wondered why your foundry didn't suggest using a gating system and pour a number of parts at one time?
I gather it's A356 aluminum alloy - seems to be the bread and butter casting alloy in these parts and the finished product doesn't seem to exhibit any of the issues of a casting with a lot of reclaim in it?

The foundry I have access to is operated by the sculpture department at my college. As a grad student I get a pass to do pretty much anything I want; interlope into other programs and departments. Its awesome. That being said, this foundry pours metal maybe 6 times a year for the sculpture students so there is a VERY loose/crude process established here.  Typically sculpture doesn't need to "work" so a lot of things that would make castings unacceptable for industry use are widely tolerated here. I blew their minds when I showed them how to do a "face coat" with chopped fiberglass in the investment. That should inform you to the caliber of work they are turning out. I asked for their advice on gating and started talking details and got blank stares in return; its something I know little about, them as well. I did one cover per investment to keep the investments physically smaller. I have only done the plaster/silica investment once before, the other times I had access to ceramic slurry investment which is much better IMHO. The castings moved around a bit and there is porosity throughout. Its not too noticeable unless you inspect close up. I would not expect them to hold oil but its for the ignition cover so its good enough.

(http://i1043.photobucket.com/albums/b436/doctorot/IMG_3517_zpsuz4tzluy.jpg)

(http://vintagekawasaki.com/webshop/images/56013-006.jpg)
Title: Re: saving a 1980 KZ750 twin
Post by: Eleganten on Jan 29, 2017, 18:25:24
Looks really good!


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Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jan 29, 2017, 18:51:51


The foundry I have access to is operated by the sculpture department at my college. As a grad student I get a pass to do pretty much anything I want; interlope into other programs and departments. Its awesome. That being said, this foundry pours metal maybe 6 times a year for the sculpture students so there is a VERY loose/crude process established here.  Typically sculpture doesn't need to "work" so a lot of things that would make castings unacceptable for industry use are widely tolerated here. I blew their minds when I showed them how to do a "face coat" with chopped fiberglass in the investment. That should inform you to the caliber of work they are turning out. I asked for their advice on gating and started talking details and got blank stares in return; its something I know little about, them as well. I did one cover per investment to keep the investments physically smaller. I have only done the plaster/silica investment once before, the other times I had access to ceramic slurry investment which is much better IMHO. The castings moved around a bit and there is porosity throughout. Its not too noticeable unless you inspect close up. I would not expect them to hold oil but its for the ignition cover so its good enough.


The expense to run a foundry class has limited the ability to teach it and much of the knowledge has been lost as a result, save for what people can find online.  For the most part, schools have shuttered programs, so to find a functioning foundry at a university at all is an achievement.  In major cities or areas where there is access to commercial foundries, the process stops at wax positives in the studio and a professional foundry casts the work.   I taught it for years, but we shuttered the metal foundry at Temple University in 2009 when we moved Tyler School of Art from Elkins Park to the main campus in N Philly.  We didn't include a metal foundry in the Sculpture program in the new facility and instead, all casting shifted to the Glass and Ceramics programs where I taught.  One exception is in Metals/CAD/CAM (Jewelry) programs, but that type of metal casting typically occurs in kilns or with torches.  It's unfortunate. 
Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Jan 29, 2017, 19:03:02
Very cool. I have been contemplating doing some cast covers for the 360 using 3D printed masters. Definitely some good motivation here.


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Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jan 29, 2017, 19:11:01
The castings moved around a bit and there is porosity throughout. Its not too noticeable unless you inspect close up. I would not expect them to hold oil but its for the ignition cover so its good enough.
Did you use flux and degassing tablets?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 29, 2017, 19:15:57
Did you use flux and degassing tablets?

negative.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jan 29, 2017, 19:32:09
You have about a 3 minute window to pour aluminum before hydrogen forms.  Drossing flux and de-gassing tablets are pretty important when you don't have the equipment to de-gas. 

http://www.ebay.com/itm/N406-Sodium-Free-Dross-Cover-Aluminum-Flux-1350-1470F-/250663652557?_trksid=p2141725.m3641.l6368

http://www.budgetcastingsupply.com/product-p/2011-010.htm
Title: Re: saving a 1980 KZ750 twin
Post by: pacomotorstuff on Jan 29, 2017, 19:42:44
I was so mesmerized by the castings, I forgot to ask you what silicone rubber(s) you used and I gather, did a vacuum debulk on the rubber before you made the moulds?
Pat
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 30, 2017, 02:16:04
You have about a 3 minute window to pour aluminum before hydrogen forms.  Drossing flux and de-gassing tablets are pretty important when you don't have the equipment to de-gas. 

http://www.ebay.com/itm/N406-Sodium-Free-Dross-Cover-Aluminum-Flux-1350-1470F-/250663652557?_trksid=p2141725.m3641.l6368

http://www.budgetcastingsupply.com/product-p/2011-010.htm
very interesting


I was so mesmerized by the castings, I forgot to ask you what silicone rubber(s) you used and I gather, did a vacuum debulk on the rubber before you made the moulds?
Pat

The rubber was leftover from another casting project, hence the two colors. I used Smooth-On's PMC line, I chucked the containers and don't remember which ones specifically. I did not use a vacuum.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 01, 2017, 04:44:59
I got the calipers mounts fitted. Should I do pocketing or holes? holes will be faster, but pocketing will be stronger. both will look cool.
Title: Re: saving a 1980 KZ750 twin
Post by: teazer on Feb 01, 2017, 22:47:43
Shoot Doc, that's a Brembo P08 if I'm not mistaken.  One of the very few calipers that was around in 72 and still good enough to be used today.  Or a Grimeca copy at least.  I can't read the cast in name.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 01, 2017, 23:55:47
Good eye, indeed it is the P08, I like the old school flavor and you can get them brand new for $130. You may already know this, but it's a semi replica of the lockheed brakes that were common on 70s racers. In fact the lockheeds were standard on the venerable Kawasaki S1. A simular Lockheed design came stock on some triumphs as well but they were cast iron bodies and pistons. I actually have two of those OEM calipers and they weigh a 3 times as much. I have the Grimeca replicas on my kz1000, and the Brembos are definitely nicer
Title: Re: saving a 1980 KZ750 twin
Post by: teazer on Feb 02, 2017, 11:47:44
I have a P08 that I was going to use on a TZ350 project to replace the heavy cast iron stock RD caliper.  The original Lockheeds are (or were last time I checked) available again.  I don't recall if they are 3 rib or 4 rib.  Good calipers for the time and still work well.

Good choice
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Feb 02, 2017, 12:08:48
Good eye, indeed it is the P08, I like the old school flavor and you can get them brand new for $130. You may already know this, but it's a semi replica of the lockheed brakes that were common on 70s racers. In fact the lockheeds were standard on the venerable Kawasaki S1. A simular Lockheed design came stock on some triumphs as well but they were cast iron bodies and pistons. I actually have two of those OEM calipers and they weigh a 3 times as much. I have the Grimeca replicas on my kz1000, and the Brembos are definitely nicer


Where did you find the new ones?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 02, 2017, 13:03:22
I have a P08 that I was going to use on a TZ350 project to replace the heavy cast iron stock RD caliper.  The original Lockheeds are (or were last time I checked) available again.  I don't recall if they are 3 rib or 4 rib.  Good calipers for the time and still work well.

Good choice

That would be the perfect brake for that bike, very cool. do you have a build thread? I think the Lockheeds made by AP look cooler as they are pretty much replicas of the originals with the ribs and all, but they are significantly more expensive. Last I checked they were $250 each,  but that was before the GBP tanked.


Where did you find the new ones?

I got mine from Bevel Heaven, but any Brembo dealer can get them.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Feb 08, 2017, 03:50:41
need some new bolts
Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Feb 08, 2017, 04:29:08
Nice work, those brackets look fantastic.
Title: Re: saving a 1980 KZ750 twin
Post by: RR100 on Feb 08, 2017, 13:20:46
love those brackets!
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Feb 22, 2017, 07:26:43
First off - thanx to CC for pointing me in this direction!

Second ......... Nice work, good to see other Lonesome Twin owner's projects - I'm now a follower.
Title: Re: saving a 1980 KZ750 twin
Post by: SrgtBear on Mar 08, 2017, 16:36:56
This build it beautiful.  Can't wait to see the next update.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Mar 15, 2017, 02:20:15
thanks guys. small update but the brakes are plumbed and cables shortened and routed.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Mar 15, 2017, 11:10:21
I love the updates in this build. Top notch.  8)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Mar 29, 2017, 03:55:16
So i have been thinking about the design for the muffler, and am wondering what size to make the baffle. The collector I made is 1.875"OD/1.75"ID. I see that Cone Engineering has their "quiet core" mufflers choked down to 1"  and they also have the straight through mufflers. Should I make the baffle smaller than the collector? I can't find any 1.875" perforated tube, but I can find some 1.75" Thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 02, 2017, 06:04:41
 .
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Apr 02, 2017, 06:45:23
Doc, that paint job is gorgeous.  Nice one.
Title: Re: saving a 1980 KZ750 twin
Post by: 540Nova on Apr 02, 2017, 08:52:13
That's awesome!


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Title: Re: saving a 1980 KZ750 twin
Post by: jag767 on Apr 02, 2017, 09:27:43
Well done, I have a few things you can paint for me   ;D
Title: Re: saving a 1980 KZ750 twin
Post by: SrgtBear on Apr 02, 2017, 09:52:12
Beautiful.


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Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Apr 02, 2017, 10:05:25
Nice job on the paint!
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 02, 2017, 12:28:42
exceptionally nice paint scheme!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 02, 2017, 18:53:55
Thanks guys. Hopefully ill have a chance this week to get it on the bike.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 03, 2017, 01:36:21
I have been fiddling around with the foot controls. got the kick-starter painted with a new detent spring and ball, shifter and rear brake arm are drilled and painted. The stock brake lever was bent pretty badly from where the PO layed it down, so I bent it back with fire. I still want it a little closer to the motor but its much better.

The brake linkage is getting fouled by the new swing arm, so I am going to cut the tab on the brake lever where the linkage connects and move it out some. The problem this creates is that the brake pedal linkage mount is now no longer planar to the rear brake drum arm, and has to be bent into a dogleg to clear the swingarm. I mashed on the pedal pretty hard and it didn't seem to bend the dogleg linkage back hardly at all, but it still makes me wonder if its good. I'm thinking about making a new linkage rod out of chromoly and doglegging it. Thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 06, 2017, 02:59:40
I decided to get rid off the stock brake pedal push pad in order to bend the brake pedal tucked in closer to the motor. I turned a steel bung and knurled an aluminum the push pad, welded that on and modded the linkage mount. I had some 1/4" - .065 wall 4130 laying around so I made a new linkage by TIG brazing a clevis to one and and threading the other, but the threads are kinda rough and shitty, which has been my experience in machining Cromoly as well. I think I might cut those threads off and braze some stainless "all-thread" on.
Title: Re: saving a 1980 KZ750 twin
Post by: SrgtBear on Apr 06, 2017, 08:28:32
I like that a lot!


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Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 09, 2017, 17:29:11
rear brake lever and linkage finished and painted. I also turned up and polished a bunch of brass washers on the lathe, for the footpegs, shock mounts, and steering stem bolt. I wanted to try and pull a little gold into the scheme since i put the gold stripe on the tank. Tons of little things have been finished. The list of remaining stuff is short. Here is a bunch of gratuitous pics of it in the sun for the first time in months.
Title: Re: saving a 1980 KZ750 twin
Post by: stroker crazy on Apr 09, 2017, 23:28:16
Beautiful work!

Crazy
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 10, 2017, 00:00:43
NICE!  So many nicely made and well engineered details!  Really like the paint scheme, but seems like it needs to be continued onto the side covers somehow - they look like they need some sort of detail since the tank is so striking.  I also like the functional fenders, but they look a bit curious - are they factory chrome? They look almost painted silver on my monitor - maybe just the pics.  Any plans to add to the pipes?  They look super nice, but I'm thinking pretty attention getting!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 10, 2017, 02:29:26
NICE!  So many nicely made and well engineered details!  Really like the paint scheme, but seems like it needs to be continued onto the side covers somehow - they look like they need some sort of detail since the tank is so striking.

I am going to run the original Kawasaki logos on the tank and the "750 Double Overhead Camshaft" badges from the Z2, that was made for the JDM, on the sidecovers.

http://www.ebay.com/itm/2FastMoto-Kawasaki-Side-Cover-Emblem-KZ750-Z2-Vintage-039-74-039-75-Badge-/201560359509?rmvSB=true



I also like the functional fenders, but they look a bit curious - are they factory chrome? They look almost painted silver on my monitor - maybe just the pics.

they are factory chrome that i put a unidirectional brushed finish on with scotch bright. front is off a kz1000LTD, rear is from a XS650


Any plans to add to the pipes?  They look super nice, but I'm thinking pretty attention getting!

I'm working on a stainless muffler
Title: Re: saving a 1980 KZ750 twin
Post by: The Jimbonaut on Apr 10, 2017, 11:52:17
Gorgeous colour and great looking bike!  I'm thinking on doing something similar with my fenders - once you'd run the scotchbrite over the chrome did you clear coat over it?  Or will the chrome still hold up (not rust or tarnish) without it?

Thanks man, and kudos on one heck of a nice looking ride
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Apr 10, 2017, 11:59:19
Geez that bike is gorgeous Doc.
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Apr 10, 2017, 16:12:07
amazing work, this thing is Beautiful!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 10, 2017, 16:36:29
Thanks guys.


once you'd run the scotchbrite over the chrome did you clear coat over it?  Or will the chrome still hold up (not rust or tarnish) without it?

Just brush them with red scotchbright. No clear. It's near impossible to go through the chrome with the scotch bright
Title: Re: saving a 1980 KZ750 twin
Post by: The Jimbonaut on Apr 10, 2017, 16:43:18
Cool, that's great to know.  Thanks man.  I had a '78 VW camper van that I sprayed the exact same green as your bike - man I'd spray everything I owned that colour if the wife would have it.  Might do it anyway.  She'll come round...
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Apr 11, 2017, 07:04:32
(https://uploads.tapatalk-cdn.com/20170411/11cc8937a096502d267ebc5139ddc949.jpg)

Done a bit of kz saving myself now, donated a pair of amals(stock carbs were leaking) to a friends project, all hooked up and time for a trial run!
Title: Re: saving a 1980 KZ750 twin
Post by: Supergyro on Apr 11, 2017, 12:55:51
Did you brush the chrome to hide imperfections, or were they clean before? It seems like a good tactic to recover some use from old chromed parts.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 11, 2017, 16:33:48
Done a bit of kz saving myself now, donated a pair of amals(stock carbs were leaking) to a friends project, all hooked up and time for a trial run!

Very cool. I have been thinking about swapping for the VM34 carbs that guys run on the XS650. Let me know how it runs with those carbs, interested in the results you get.


Did you brush the chrome to hide imperfections, or were they clean before? It seems like a good tactic to recover some use from old chromed parts.
Bingo! They weren't terrible shape but a lot of small scratches in the chrome. this just makes it uniform and intentional.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Apr 12, 2017, 01:53:04
Very cool. I have been thinking about swapping for the VM34 carbs that guys run on the XS650. Let me know how it runs with those carbs, interested in the results you get.

Bingo! They weren't terrible shape but a lot of small scratches in the chrome. this just makes it uniform and intentional.
Except for the basic jetting issues it ran unexpectedly fine, ridiculously good pull at open throttle, but a little uneven at low rpms, feels like i accidentally put the needles at different heights, and throttles are not synced. Does not feel congested with those small 30mm carbs.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Apr 16, 2017, 04:45:37
Damn I missed this update.  The bike looks stunning!  The details you have put hours into really make it man.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Apr 16, 2017, 04:57:31
Except for the basic jetting issues it ran unexpectedly fine, ridiculously good pull at open throttle, but a little uneven at low rpms, feels like i accidentally put the needles at different heights, and throttles are not synced. Does not feel congested with those small 30mm carbs.
Needles were uneven, reportedly it has lively pull now!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 23, 2017, 16:23:36
scheming...
Title: Re: saving a 1980 KZ750 twin
Post by: Luugo86 on Apr 23, 2017, 18:12:48
 I really like the look of this bike. It looks like it will be an absolute blast to ride.
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Apr 24, 2017, 13:11:40
that exhaust scheme looks like a Kerker to me  ;)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 24, 2017, 14:20:40
Sure does! nothing says 70's performance like a megaphone to me.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 03, 2017, 04:01:18
I have run into an issue with the upper engine mount and Im hoping to get some insight here. For some reason the mounts that bolt to the valve cover or don't even come close to lining up with the mounting holes. The same thing happened to me on my KZ400 when I rebuilt the top end. I ended up having to hog out 7mm on the mount plate holes on that to get it to bolt up.

I need to remake the head mounts on this 750 anyway because this is where the coil mounts and my aftermarket coil does not fit with the stock engine mounts. No problem, I can make a motor mount easy enough, but then I realize that the mating surface on the valve cover is not perpendicular to the bolt hole on the valve cover. The valve cover has about 5 degrees of draft on it so it can be cast but the mounting points were never machined flat. This causes me to believe that the reason the original mounts no longer fit is when they are torqued down they bend out of shape so once you remove them they no longer fit.  The original mounts also have a ton of slop in them.

 I was going to make some trick mounts out of aluminum plate, but now I don't know what to do. The original ones are stamped steel with this cheesy bend in them that probably helps deal with the fit issues. right now i see two routes of action. take the valve cover off, mill the mounting points flat and make the aluminum plates, or file out the existing motor mounts and mod them to accept the new coil, maybe weld in a washer to help take out the slop. Thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on May 03, 2017, 08:44:24
my CM had similar head mounts and to get them to line up you put them on lose, then get the bolts in, then torque everything down and yes they deform or conform to fit. also you need to put them back on the same side and way they came off.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on May 03, 2017, 11:22:35
I'd guess that if you loose all the other engine mounts, you will be able to assemble the uppers.  Presuming you can, you likely will be better served to use them if you can alter them to fit your coil setup.  You could fab them up from aluminum, but this sort of part often suffers from fatigue cracking unless carefully designed. 
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on May 03, 2017, 12:01:04
Interesting hangup Doc.  They sure came out easy eh?    I haven't tried bolting mine back in lately but I remember the top mounts were side specific.   I had presumed first off, last on but maybe I'll have to check the fit up in mine for this same issue.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 03, 2017, 13:34:03
Because I oversized the engine mount bolts there is very little slop there, so loosening the mounts wouldn't do anything  because some of the holes are a good 5-7mm off. Logically it would seem that this mount would put a lot of strain on the motor if it was assembled loose and then tightened as JP suggested. I wonder if this is a contributing factor as to why these motors so frequently have headgasket leaks.
I didn't even remove the motor on my kz400 and same thing happened. The mounts are sided but it is very obvious which side is which because the mounts have nuts welded to them, and its been so long since i pulled the motor I don't remember if the bolts were tough to get out. I was thinking about the fatigue cracking as well, the steel is probably pretty forgiving here. I guess I will try modifying what I have instead.
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on May 03, 2017, 13:41:49
Because I oversized the engine mount bolts there is very little slop, so loosening the mounts wouldn't do any thing particularly because some of the holes are a good 5-7mm off. I didn't even remove the motor on my kz400 and same thing happened. The mounts are sided but it is very obvious which side is which because the mounts have nuts welded to them. I was thinking about the fatigue cracking as well, the steel is probably pretty forgiving here. I guess I will try modifying what I have instead.

There's the reason, on the engine the bolts usually have some open space in the holes that allow the motor to move when they are lose, then when you get everything attached you torque them down to stay in place. did you put never seize etc. on the shafts of the bolts? if not being oversized even a little corrosion will make them a bitch to get out if you need to down the road.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on May 03, 2017, 15:01:45
Is there room to run dampeners/isolators, either between brackets and frame, or have them through bolt?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 04, 2017, 05:33:57
Is there room to run dampeners/isolators, either between brackets and frame, or have them through bolt?
I was thinking about something like this. I have seen some British bikes do this (commandos?) I wonder if it is worth the effort though.


There's the reason, on the engine the bolts usually have some open space in the holes that allow the motor to move when they are lose, then when you get everything attached you torque them down to stay in place. did you put never seize etc. on the shafts of the bolts? if not being oversized even a little corrosion will make them a bitch to get out if you need to down the road.

Most of the holes maybe had .5-1mm of slop; nowhere near the 5-7mm i'm seeing up top, but i don't deny that that very well could contribute to the problem. I did put a bit of anti sieze on the bolts, but i'm not concerned. Guys have been over-sizing the mounting bolts on their KZ1000s for years and the only story I have heard of the bolts getting stuck from corrosion was a guy that lived right on the ocean and parked his bike outside, thing looked like boat anchor but still ran.
Title: Re: saving a 1980 KZ750 twin
Post by: john15511 on May 04, 2017, 17:01:57
I have been reading your thread for the past 2 days and just caught up.  AMAZING BUILD!


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Title: Re: saving a 1980 KZ750 twin
Post by: Nebr_Rex on May 04, 2017, 23:19:16
I would use tubing between the frame rails and drop say a piece of 10ga. straight down to the engine.


.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 05, 2017, 04:14:47
I would use tubing between the frame rails and drop say a piece of 10ga. straight down to the engine.


.

It thought about that but it doesn't allow the coil to be mounted under the tank. A member over at KZR suggested the use of "spherical washers" to deal with the tolerance issues, I had never heard of these before, pretty cool piece of hardware. The only spherical washers i have found can compensate for 3 degrees, but i figure one at the valve cover and one at the frame mount and it would work. I need to evaluate my options.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 21, 2017, 23:50:43
Got started on the muffler, ill let the pictures do the talkin. I need to decide on what style of end-cap I will turn out of aluminum.
Title: Re: saving a 1980 KZ750 twin
Post by: interceptor on May 22, 2017, 08:30:04
You do really nice work.  That muffler looks fantastic.  I have really enjoyed your build progress!!
Title: Re: saving a 1980 KZ750 twin
Post by: Tune-A-Fishİ on May 22, 2017, 10:19:50
#2 ;)
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on May 23, 2017, 08:45:52
Yep #2 middle one. that's the best look for the bike.
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on May 23, 2017, 13:19:13
#2
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on May 23, 2017, 17:43:36
Whoa, amazing craftsmanship again man!  Love the little tool to make the flares and the fact that you polished the welds.  Even though they were nice, it has become such a fad to have the segmented tig'd exhausts!

Edit:  End cap No3 for sure!
Title: Re: saving a 1980 KZ750 twin
Post by: stroker crazy on May 23, 2017, 22:57:30
End cap No3 for sure!

My thought also; #2 looks good but would probably accumulate dirt, grease, carbon, etc.

Crazy
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 24, 2017, 01:55:56
Thanks guys. i just bent some chromoly tube for the passenger footpegs/hanger for the exhaust. I think i will have some time tomorrow to work on it.

Whoa, amazing craftsmanship again man!  Love the little tool to make the flares and the fact that you polished the welds.  Even though they were nice, it has become such a fad to have the segmented tig'd exhausts!
Thanks! I hate trends, but by building this style of bike I'm already chasing a trend so I'm trying to keep it different in subtle ways.

My thought also; #2 looks good but would probably accumulate dirt, grease, carbon, etc.

Crazy

Yeah #2 is probably the least practical, but I think I like it the best because it looks like the old kerker baffle, which I am drawing on for inspiration for that old school go fast look.

 I had this  idea to make a badge in the same font as the old Kerker logo but say KILLER instead. But then i thought... why? because killer is bad ass? I don't know. I feel like a trick exhaust needs a sweet badge.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on May 28, 2017, 12:34:52
I feel like a trick exhaust needs a sweet badge.

It does need a sweet badge.  Looks awesome.
Title: Re: saving a 1980 KZ750 twin
Post by: conghos on May 28, 2017, 15:01:54
4 into 1 Killer made in Argentina in the 80s(https://uploads.tapatalk-cdn.com/20170528/740b8c8f9e1ff4e7b24089c4ff0b547a.jpg)

Enviado desde mi Lenovo A6020l37 mediante Tapatalk

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 28, 2017, 15:23:35
4 into 1 Killer made in Argentina in the 80s(https://uploads.tapatalk-cdn.com/20170528/740b8c8f9e1ff4e7b24089c4ff0b547a.jpg)

Enviado desde mi Lenovo A6020l37 mediante Tapatalk

Haha! just goes to show that NO idea is truly original
Title: Re: saving a 1980 KZ750 twin
Post by: conghos on May 28, 2017, 21:59:35
You are doing a bodacious work on that z750... here's another photo of the badge taken from a friend's bike.

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 30, 2017, 01:23:48
thanks man. that badge is cool. i need to think of something to put on mine.

small update but I really liked how simple this ended up being. When the forks were turned fully to the left the throttle cables would push over to the far side of the handle bar riser bolt, then when turned back they would get stuck there and cause the front end to get stuck, not good. I made this dead simple hook that bolts on to the handlebar riser to keep the cables tidy and also prevents them from rubbing on the headlight/tach
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 01, 2017, 03:20:32
Made progress on the hanger and exhaust mount.  I'm using some Tarrozi folding pegs that were intended for a different project. They're a tad long for passenger pegs so I will probably cut them down eventually. The mounting bungs i originally turned were too big to look good so I remade made them. I'm not sure I like the placement of the "load spreader" (for lack of a better term.) The part on the muffler that actually welds to the muffler, not the tab that connects to the rubber mount. It looks a bit odd to me, i might end up cutting a trapezoidal one to follow the lines better. I think there has to be a cooler way to weld on the tab but I'm not sure. Also I'm wondering if its thick enough; its only .065" while most  i've seen have been .125" I don't want it to crack.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Jun 01, 2017, 03:39:49
Turning out most awesome
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 03, 2017, 01:52:04
Here is the revised mount. the weld got a little funky where the load spreader meets the muffler cause I put some solar flux behind it to minimize "sugaring"  and the solar flux contaminated the weld a bit. I will hit it with an "air file" and no one will be the wiser. All that's left on the exhaust is the end cap, packing, and springs/holders for the slip fit.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Jun 05, 2017, 17:00:27
Got a pic from a little bit away? I'd love to see the whole thing with the exhaust now.  She's awesome man!!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 07, 2017, 02:11:33
Got a pic from a little bit away? I'd love to see the whole thing with the exhaust now.  She's awesome man!!

Small garage ;) I'll role her out soon. I did finish the exhaust, but nee to trim a tiny bit off the exhaust flanges and pack the muffler first before it can go back on. Exhaust cap came out pretty nice but i want to trim a little bit more off the lip.
Title: Re: saving a 1980 KZ750 twin
Post by: Luugo86 on Jun 07, 2017, 04:48:08
Nice work
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 07, 2017, 13:18:30
I don't think it'll look right on that bike, better send that pipe to me instead.  ;)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 08, 2017, 16:46:53
i put a little taper on the end cap.
Title: Re: saving a 1980 KZ750 twin
Post by: 540Nova on Jun 08, 2017, 18:05:03
That's an old bicycle in the background of pic #5, downtube shifters!

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Title: Re: saving a 1980 KZ750 twin
Post by: 540Nova on Jun 08, 2017, 18:07:09
That's an old bicycle in the background of pic #5, downtube shifters!

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Looks like an old Vitus or Alan.

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Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Jun 08, 2017, 18:32:08
She's looking fantastic man!!! Thanks for wheeling her out for some beauty shots.   8) 8)
 
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Jun 09, 2017, 13:11:31
Very Nice work !!!
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Jun 09, 2017, 13:16:23
Nice fecken job, that looks incredible.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 09, 2017, 19:24:46
Thanks guys! Can't wait to hear it!
Title: Re: saving a 1980 KZ750 twin
Post by: Popeye SXM on Jun 09, 2017, 20:20:32
Very impressive work, love that exhaust!
Title: Re: saving a 1980 KZ750 twin
Post by: KZam440 on Jun 09, 2017, 23:32:10
Wow, I still can't fix my broken kz

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Title: Re: saving a 1980 KZ750 twin
Post by: Supergyro on Jun 11, 2017, 01:24:34
Beautifully done! Fantastic work all around.
Title: Re: saving a 1980 KZ750 twin
Post by: JadusMotorcycleParts on Jun 13, 2017, 15:43:28
She's looking fantastic man!!! Thanks for wheeling her out for some beauty shots.   8) 8)

+1  8)
Title: Re: saving a 1980 KZ750 twin
Post by: Green199 on Jun 14, 2017, 10:48:28
I think you may have built my dream motorcycle. Damn nice work Doc.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 17, 2017, 04:35:29
I definitely didn't make it easy on myself to pack the muffler with the kinks in the can. I bought a kit with stainless mesh, stainless mat, and fiberglass mat, its is in there very snugly. The perforated core isn't attached on either end but is wedged between the two ends, hopefully this will negate fatigue issues. I also finished the left passenger peg.
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Jun 19, 2017, 08:53:13
Nice work!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 25, 2017, 04:17:44
Got around to finishing the top motor mount. I ended up doing something similar to what NebrRex suggested. I used a 3/8" reamer in a hand drill to bore out the mounts and at the same time got them pretty close to axial, they were a little off before preventing a bolt through bolt mounts, so now I can through bolt side to side with spacers so it not only supports the motor but ties it all together and increases frame rigidity. I also milled the valve cover to remove the draft on it and now the mounting points are parallel. I ended up having to offset the coil to make clearance for the throttle cables and electrics that will go through the backbone as well. I like that you can see the mounts if you bend down to inspect the bike. I also refinished the tank and side cover badges I bought as I hate flat black paint, and the white didn't match the shocks or tank. details....
Title: Re: saving a 1980 KZ750 twin
Post by: stroker crazy on Jul 25, 2017, 06:09:04
That has to be the best top mount ever!

Crazy
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Jul 25, 2017, 07:21:51
That has to be the best top mount ever!

Crazy
Looks bomb proof.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on Jul 26, 2017, 11:03:51
Dude. Slick work, as per usual.  This is easily one of my favorite bikes on here :)  8) 8) 8)
Title: Re: saving a 1980 KZ750 twin
Post by: CrabsAndCylinders on Jul 26, 2017, 14:58:05
Love that top motor mount!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 26, 2017, 17:10:00
Thanks guys
Title: Re: saving a 1980 KZ750 twin
Post by: dakine_surf on Jul 27, 2017, 17:45:58
Small garage ;) I'll role her out soon. I did finish the exhaust, but nee to trim a tiny bit off the exhaust flanges and pack the muffler first before it can go back on. Exhaust cap came out pretty nice but i want to trim a little bit more off the lip.
Just catching up, love the exhaust, it really is amazing.  Your fab skills are top notch, really beautiful work!  That table is also beautiful, did you build that as well?


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Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 28, 2017, 14:33:11
Thanks man. Yes, I made the table. Solid hickory top brushed steel base.
Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Jul 28, 2017, 14:42:14
Nice work on the table, did you fab those tapered legs yourself?
Title: Re: saving a 1980 KZ750 twin
Post by: dakine_surf on Jul 28, 2017, 14:47:52
Awesome, I really like that table clean lines, the dowels add nice contrast...

I love hickory but haven't used it other than a few axe and hatchet restorations.  I just got a large slab of pecan that will become a dining table, I hear it is similar to hickory but I haven't worked with it either on any large projects...

Really nice work


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Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 28, 2017, 14:52:22
Nice work on the table, did you fab those tapered legs yourself?
Yes 40 feet of weld in the legs alone

Hickory is really tough to work with. Wants to tear out, even drilling it with a brand new brad point it wants to tear out, dulls sandpaper very quickly. Insanely strong though, I got it real cheap so I used it, don't think I would use it again.
Title: Re: saving a 1980 KZ750 twin
Post by: dakine_surf on Jul 28, 2017, 16:35:11
Yes 40 feet of weld in the legs alone

Hickory is really tough to work with. Wants to tear out, even drilling it with a brand new brad point it wants to tear out, dulls sandpaper very quickly. Insanely strong though, I got it real cheap so I used it, don't think I would use it again.
Yeah that's what I hear about this particular slab of pecan I have too... super hard, not easy to work with but the results are normally worth it


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Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 29, 2017, 19:52:50
I got the ignition system installed and I was dying to hear this thing run, so I hot wired it. This motor has great compression and is very difficult to turn over with the kick-starter even with my 230lbs behind it, but it still started up first kick!

https://youtu.be/lnhF_QU0-jY
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 29, 2017, 23:37:03
Awesome Doc.  That pipe you made sounds great. 
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Jul 30, 2017, 22:08:19
Sound great
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 08, 2018, 18:04:56
I decided to scrap the custom foot-pegs I was working on and modify the stock brackets to use Tarozzi pegs, I also turned some aluminum spacers so they are solid mounted now. all that remains is wiring, fuel plumbing, and a license plate holder. gettin close!
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jan 08, 2018, 23:12:05
Glad to see you back on this one too.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jan 09, 2018, 05:52:02
forgot to some add these pics of the new shifter. I went a little overboard on the speed holes with the stock shifter so I made a new one out of thin wall steel tube, and TIG brazed the fittings on. It threads into an aluminum Tarozzi splined clamp.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Mar 19, 2018, 17:10:12
I'd like to get some opinions here as I have compromised the strength of a semi-structural screw and I don't want my own "genius" to kill me. I drilled and tapped this head-stock screw to mount an oil light. The difference between the OD minor thread diameter  and the ID major thread diameter is about 4mm so I am left with 2mm thick walls. This screw appears to pretty lightly loaded as the steering stem fits into the top triple and is firmly clamped with a pinch bolt. I torqued the modified screw to the factory value of 36ft/lbs and it seems fine. I have also seen aluminum aftermarket replacement screws available for this application so I can't imagine that this is super critical strength wise.  thoughts?
Title: Re: saving a 1980 KZ750 twin
Post by: teazer on Mar 19, 2018, 18:25:54
I replaced the steel top nut on a set of forks with an aluminum bolt from a late model TZ250.  It does not need to be very strong as there is not a lot of force on that nut/bolt. Bottom triple clamp does most of the work.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Mar 19, 2018, 19:18:50
The bolt will be fine.  You could ride around with the bolt left out entirely with no real cause for concern as long as the three pinch bolts are properly in place.  Cool spot for the light - how are you routing the wire?
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Mar 19, 2018, 19:38:12
Plus, dirt bikes have holes there for the gas tank vent tube.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Mar 19, 2018, 21:00:20
Thanks for the input fellas. I'm going to paint it black this afternoon.

The bolt will be fine.  You could ride around with the bolt left out entirely with no real cause for concern as long as the three pinch bolts are properly in place.  Cool spot for the light - how are you routing the wire?

that was the conclusion I came to as well. The wire will go out the bottom of the steering neck then up and back into the loom.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Mar 21, 2018, 05:13:49
blasted and painted with Gun Kote. i tested it and it is really bright.
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Mar 21, 2018, 07:43:56
Its in the detail.  Nice !
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 07, 2018, 09:24:18
quick question on wiring the nuetral indicator light;
factory wiring has 12V+ to indicator light > then to neutral switch which grounds on the engine.

this wont work in my tach because the indicator light shares a common ground wire. I think I could use a relay to sort this out, but I don't want to use a big standard one. This tiny LED probably needs less than 0.5 amps. will something like this work?

https://www.jameco.com/z/EDR201A12Z-Excel-Cell-Electronics-Relay-Dip-SPST-12VDC-1A-Cont-1K-Ohm-Coil-2_106472.html

Suggestions?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 27, 2018, 03:47:02
I have this spare 20mm GSXR750 axle Id like to use. Its hollow and weighs half of what my solid ones does. The problem is its too long. The end where the threads are is swagged to 18mm. If i cut this portion off and cut 20mm threads on the main shaft I think the wall thickness will be like 1-2mm thick in the minor thread, so I don't think I can realistically do that. I'm thinking about cutting off the hex head, trimming it to length, and soldering  on a new hex. I will pin the hex to the shaft as well for safety's sake. I found this solder which is very low heat (430F/221C) so I believe I should be able to solder the nut on there without removing the temper.
http://www.harrisproductsgroup.com/en/Products/Alloys/Soldering/Lead-Free-Solders/Stay-Brite-Kit.aspx

Is this a bad idea?
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Apr 27, 2018, 09:55:00
I've done similar where I weld on the hex head plus a short length, then machine it back down clean. 
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 27, 2018, 11:23:34
I imagine that would work fine, presuming it is silver soldered.  Keep in mind the job the axle needs to do.  While it may seem that it is principally loaded in shear to keep the wheel from falling off, it is also loaded in tension.  The clamping force is much more important than may be intuitively obvious.  Keeping the swing arm (or fork legs), spacers, inner bearing races, and any other components tightly clamped together makes the assembly a rigid structural component that aids substantially in keeping the arm (or forks) from twisting and deforming under load.  So all the mating surfaces need to be nice and square and flat, and at least as large in o.d. as the o.d. of the inner races.  The larger the diameter of these parts, the greater the structural benefit.  As long as your soldered joint withstands the needed clamping pressure you will be fine - so use a high content of silver.  I doubt there is much special about the axle as far as heat treatment, so you should be fine heat wise.  Personally I would not hesitate to simply weld it.

Looks like your little relay would be fine.  Rather a pain to get the neutral light going though!  Any chance you can isolate the indicator so you can power it up inside the tach and use the bikes factory switched ground?
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on Apr 27, 2018, 11:50:52
I imagine that would work fine, presuming it is silver soldered.  Keep in mind the job the axle needs to do.  While it may seem that it is principally loaded in shear to keep the wheel from falling off, it is also loaded in tension.  The clamping force is much more important than may be intuitively obvious.  Keeping the swing arm (or fork legs), spacers, inner bearing races, and any other components tightly clamped together makes the assembly a rigid structural component that aids substantially in keeping the arm (or forks) from twisting and deforming under load.  So all the mating surfaces need to be nice and square and flat, and at least as large in o.d. as the o.d. of the inner races.  The larger the diameter of these parts, the greater the structural benefit.  As long as your soldered joint withstands the needed clamping pressure you will be fine - so use a high content of silver.  I doubt there is much special about the axle as far as heat treatment, so you should be fine heat wise.  Personally I would not hesitate to simply weld it.

Looks like your little relay would be fine.  Rather a pain to get the neutral light going though!  Any chance you can isolate the indicator so you can power it up inside the tach and use the bikes factory switched ground?
If its hardened its likely to be only an anneal, and not critical in the hex end anyway. Check with a file.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Apr 27, 2018, 12:01:51
Most forks are either clamping the axle on both ends, or the fork is threaded at one end and clamped at the other end.  There doesn't have to be any force at all against the hex end.  He could cut the head off completely at right length to meet the outer edge of the fork and would still work fine.  The hex head is there to hold the axle while you thread the bolt at the other end.  It's more a redundant retainer than anything.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Apr 27, 2018, 12:04:44
I was thinking that was a rear axle, not a front.
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 27, 2018, 13:08:16
There doesn't have to be any force at all against the hex end.

With respect, this is simply not so, at least in this context.  I believe this particular bike does indeed have a front axle threaded on both ends (I believe we were talking about the rear, but the parts end up functioning the same regardless of the design).  It is important to understand that the axle assembly is supposed to function just like a fork brace to both stiffen the whole fork assembly in torsion (bars turn, wheel doesn't) and to keep the two forks telescoping together as a single unit.  The larger the diameter of the axle (assembly), the greater the stiffness of the fork.
Indeed, you could leave the axle assembly loose and clamp it into the ends of the fork lowers.  The result would be an assembly that would all stay together, but would loose very substantial strength from two sources.  First, the slack in the loose threaded connections will allow motion in the assembly.  This alone will impact the stiffness of the system, and cause wear in the threads that would never otherwise occur with correct assembly.  But let's say there is no motion here.  If that is the case, the strength of the element connecting the two legs is just the diameter of the axle itself.  The correct procedure is to clamp all the components together with the axle first.  This (in the main) makes the functional diameter become much larger and much stiffer, the same as a large diameter tube is much stronger than a smaller tube of the same weight.  Then, when you clamp the assembly into the fork legs, you gain this very large improvement - the effective axle diameter becomes the same as the smallest o.d.sleeved component (spacer, inner bearing race, speedo drive, etc.).  If the axle nuts are not tight enough, the assembly is much more flexible.  The fork lowers have the clamps because there can't be any axial pressure on the fork legs.  If there is, the forks will bind.  This is not a factor at the swing arm, but the principles are the same otherwise.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Apr 27, 2018, 15:17:49
With respect, this is simply not so. I believe this particular bike does indeed have a front axle threaded on both ends (I believe we were talking about the rear, but the parts end up functioning the same regardless of the design).  It is important to understand that the axle assembly is supposed to function just like a fork brace to both stiffen the whole fork assembly in torsion (bars turn, wheel doesn't) and to keep the two forks telescoping together as a single unit.  The larger the diameter of the axle (assembly), the greater the stiffness of the fork.
Indeed, you could leave the axle assembly loose and clamp it into the ends of the fork lowers.  The result would be an assembly that would all stay together, but would loose very substantial strength from two sources.  First, the slack in the loose threaded connections will allow motion in the assembly.  This alone will impact the stiffness of the system, and cause wear in the threads that would never otherwise occur with correct assembly.  But let's say there is no motion here.  If that is the case, the strength of the element connecting the two legs is just the diameter of the axle itself.  The correct procedure is to clamp all the components together with the axle first.  This (in the main) makes the functional diameter become much larger and much stiffer, the same as a large diameter tube is much stronger than a smaller tube of the same weight.  Then, when you clamp the assembly into the fork legs, you gain this very large improvement - the effective axle diameter becomes the same as the smallest o.d.sleeved component (spacer, inner bearing race, speedo drive, etc.).  If the axle nuts are not tight enough, the assembly is much more flexible.  The fork lowers have the clamps because there can't be any axial pressure on the fork legs.  If there is, the forks will bind.  This is not a factor at the swing arm, but the principles are the same otherwise.

You really need to read up on this more.  Here is the picture he posted of the axle.

(http://www.dotheton.com/forum/index.php?action=dlattach;topic=66016.0;attach=203951;image)

The parts do not function the same front and back.  By having the bottom of the forks clamp, that is what is stiffening the front end, not having it threaded in or providing force to the underside of the hex cap.  The binding of the forks onto the axle is doing the work.  Notice one end of the axle in the pic does not have a hex bolt.  If it were important to provide force torquing down on that, it would not be designed that way.  Many, many, many axles including my BMW F650 and all modern Suzuki sport bikes are made without a cap at all. 

(http://www.dotheton.com/gallery/77150-190218144314-3323524.jpeg)

Here is a VZ800 front end.  The axle is not capped at all.  You thread the axle into the left fork and clamp with the right.  There is zero force squeezing the forks together.  A shoulder on the axle works against the spacers and the bearings keeping the wheel parts tight together, but the fork is separate from that force.

(http://uploads.tapatalk-cdn.com/20161122/be1d7f1b16d02b5e591f6fcdf200e031.jpg)

Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 27, 2018, 15:47:45
This is for the rear.  I have a nice stainless axle nut that is made out of 316 I would like to use. I was a little worried about welding dissimilar metals so that's why I was thinking solder as well, but after doing some research I believe using 309L should work fine
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 27, 2018, 17:32:46

The parts do not function the same front and back.

Actually they DO end up the same - there are just a few extra parts needed in the front to accommodate the telescoping parts.


By having the bottom of the forks clamp, that is what is stiffening the front end, not having it threaded in or providing force to the underside of the hex cap.  The binding of the forks onto the axle is doing the work.  Notice one end of the axle in the pic does not have a hex bolt.  If it were important to provide force torquing down on that, it would not be designed that way.  Many, many, many axles including my BMW F650 and all modern Suzuki sport bikes are made without a cap at all. 
Here is a VZ800 front end.  The axle is not capped at all.  You thread the axle into the left fork and clamp with the right.  There is zero force squeezing the forks together.  A shoulder on the axle works against the spacers and the bearings keeping the wheel parts tight together, but the fork is separate from that force.


Absolutely agree with all of this!  Evidently my communication skills are as poor as my reading ability.  In all cases, the TENSION in the axle itself is important in keeping all of the various wheel assembly components together.  Having these parts clamped tightly together is fundamental to how stiff this assembly is.  At the rear, the swing arm is part of this assembly, so it gets clamped with all the other bits.  On telescopic forks (99.99% of them anyway), either one of the legs or none of the legs is part of this assembly.  (In the case of one leg incorporated, this in fact IS exactly like the swing arm situation sans one side, which obviously must be fixed independently to prevent fork bind).  Either way, the axle ALWAYS has to provide clamping force.  In the case of one leg being incorporated, it is clamped into the assembly and this clamping force provides the stiffness at the connection.  The other end "floats" in the independent clamp on the other leg until it is tightened and this clamping force provides the stiffness there.  This connection is not on the axle, but on the much larger diameter nut, which, in being previously tightened down with the wheel assembly bits effectively becomes a larger diameter axle.  This of course is the same for assemblies with a nut clamped by BOTH fork legs.  Once the axle assembly is tight, installation into the forks can be accomplished without tweaking the forks out of align.  But the axle itself MUST clamp the wheel components together tightly first in order to maintain the structural strength of the assembly.  That's the point I feel important.  Sorry it took me so long to make it!

Apologies for jacking the thread - I shall work on explaining more clearly on the first pass! (as well as my reading skills!)
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 27, 2018, 17:45:16
This is for the rear.  I have a nice stainless axle nut that is made out of 316 I would like to use. I was a little worried about welding dissimilar metals so that's why I was thinking solder as well, but after doing some research I believe using 309L should work fine

Maybe have a look at 317L if you are determined to make one from stainless.  Should be reasonably easy to get.  That said,  IMHO stainless steels on the whole might not be the best choice for an axle.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 27, 2018, 20:20:15
The axle, I assume, is some type of chromoly. The nut I want weld to it 316 stainless. As far as I can tell ER309L is the preferred filler rod for this application 317 seems to be for dissimilar stainless alloys. I will pin it for added safety, cause I'm a belt-and-suspenders guy when it come to this type of thing. Pro Bolt sells these nuts specifically for motorcycle axles so i can't imagine its too much of a problem.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 28, 2018, 20:32:09
Finally had the time to cut and buff the paint. The result is dead flat with no definition line over the stripes. I also put on the badges.Ive been tinkering with the wiring off and on for months and it is finished. I did a bit of driveway tuning learned about the one year specific pilot screws to this year. Rounded up the nessecary parts and it's synced and seems to run great. All that remains to sort is an axle and a license plate. The latter of which should  be here ina week or so.
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Apr 28, 2018, 20:42:40
I love that green! That's close to the color I was leaning towards on my 1000. Very nice man !!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 28, 2018, 20:55:09
Thanks man. It looks even better in the sun
Title: Re: saving a 1980 KZ750 twin
Post by: The Jimbonaut on Apr 28, 2018, 21:18:18
Dude.  Just... dude. 

This is glorious.  Skills to pay the bills.  Absolutely terrific looking bike, and that colour!  Doing Kawasaki proud.  Incredible looking bike man, massive kudos. 
Title: Re: saving a 1980 KZ750 twin
Post by: CrabsAndCylinders on Apr 29, 2018, 01:14:28
I love that green! That's close to the color I was leaning towards on my 1000. Very nice man !!

I love it too!
Title: Re: saving a 1980 KZ750 twin
Post by: The Limey on Apr 29, 2018, 05:11:56
Oh yeah baby.  Bikes on this forum are judged by the turmoil they cause in my Y fronts, the famous brown ones with the orange trim.  Well, I can tell you they're currently stretched to the limit of the elastics ability to contain the swelling beneath, such is the pleasantness of this bike.

At first glance, utterly traditional, but a closer look reveals cleverly integrated modern detailing.  Very cleverly done.  One of my favourite bikes of all time too - Z1easque styling with a brawny, manly, none-of-your-new-fangled-four-cylinder-rubbish-here-son big twin motor.  Love it.  I want this bike soooooo bad.
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Apr 29, 2018, 09:57:48
Anoter botm coming I see lol looks amazing doc
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on Apr 29, 2018, 14:17:29
You set a high bar sir.  Superb as usual!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Apr 30, 2018, 15:05:57
thanks guys! this forum has always helped with motivation.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Apr 30, 2018, 16:01:06
thanks guys! this forum has always helped with motivation.

It's over the top gorgeous Doc. 
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 02, 2018, 04:06:55
Ill square it up on the lathe tomorrow.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on May 02, 2018, 04:11:41
Keep them nice couleurs..
Title: Re: saving a 1980 KZ750 twin
Post by: jpmobius on May 02, 2018, 12:07:11
That's the job!  Now, if you only had a lovely radiused washer to fit under that filet weld under the head . . . .
Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on May 02, 2018, 13:09:08
sexy welds !  I agree keep it looking just like that ! and what a weight difference...wow
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 02, 2018, 16:07:32
Sorry guys the rainbow is going. It doesn't fit the rest of the bike.
Title: Re: saving a 1980 KZ750 twin
Post by: slikwilli420 on May 02, 2018, 16:58:50
Really excellent work all around. I kept an eye on your 1000 project but just found this. Im a really picky guy and each component is something I would use. Well done.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 13, 2018, 19:05:08
First ride was a reasonable success! its got just enough power to be pretty fun, the exhaust has a great tone to it. Not too loud at idle but pretty rowdy when you get on it. The brakes are fantastic. I rode it to my graduation and hooned around a bit there afterwards with my robes on, my parents think I'm crazy. I put about 70 miles on it yesterday.

The jetting is pretty close, think I may need to go one bigger on the main and down a notch on the needle. I'm running into what i think is fuel starvation. When I'm on the highway, after a several seconds of going WOT its starts to miss and wont accelerate anymore like its running out of gas. if i back off for a bit and cruise, it seems like the float bowls refill and I can go WOT for a bit again until it starts missing again. WOT pulls from a stop to 5th gear are no problem its the extended WOT at 60+ where it happens. I have a cheapo petcock, I'm wondering if its not passing fuel fast enough. suggestions?
Title: Re: saving a 1980 KZ750 twin
Post by: CrabsAndCylinders on May 13, 2018, 19:29:10
Nice, very nice.
Title: Re: saving a 1980 KZ750 twin
Post by: Nebr_Rex on May 13, 2018, 23:08:34
First ride was a reasonable success! its got just enough power to be pretty fun, the exhaust has a great tone to it. Not too loud at idle but pretty rowdy when you get on it. The brakes are fantastic. I rode it to my graduation and hooned around a bit there afterwards with my robes on, my parents think I'm crazy. I put about 70 miles on it yesterday.

The jetting is pretty close, think I may need to go one bigger on the main and down a notch on the needle. I'm running into what i think is fuel starvation. When I'm on the highway, after a several seconds of going WOT its starts to miss and wont accelerate anymore like its running out of gas. if i back off for a bit and cruise, it seems like the float bowls refill and I can go WOT for a bit again until it starts missing again. WOT pulls from a stop to 5th gear are no problem its the extended WOT at 60+ where it happens. I have a cheapo petcock, I'm wondering if its not passing fuel fast enough. suggestions?
Had that same problem on my first KZ1000, it was a small fuel filter for me.


.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on May 16, 2018, 16:15:46
Get a Pingel for fuel, they have a screen filter already and flow second to none.  Congratulations on graduation!!!    I love your KZ twin, riding it to graduation was perfect!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 17, 2018, 20:00:10
Thanks guys.

I took the Pingel off my kz1000. At the very least it makes routing the fuel lines WAY easier, and looks a lot better. Unfortunately it didn't solve the problem. I popped the gas cap open and rode it like that as well thinking maybe it wasn't venting properly but that had no change. I'm gonna pull the carbs off and inspect the fuel inlets and float valves. Scratching my head here. suggestions?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 18, 2018, 19:36:02
So the float valves were 2.0, I switched them to 2.5 and the problem went away. it also richened everything else up and the bike is happier on the whole. Im thinking about switching them to a 2.8 just to ensure the float valve isn't acting as my main jet.

My question is; why would they install small float valves? wouldn't you want to have the biggest possible float valve to ensure fuel delivery, and let the jets do the fuel metering?
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on May 19, 2018, 03:19:50
Emissions maybe.
Title: Re: saving a 1980 KZ750 twin
Post by: CrabsAndCylinders on May 19, 2018, 03:56:02
That's interesting, I don't believe I have heard of going to a bigger float valve before.
Title: Re: saving a 1980 KZ750 twin
Post by: datadavid on May 19, 2018, 03:59:57
In europe at least, 2.5 valve is stock for these.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on May 22, 2018, 13:49:14
So the float valves were 2.0, I switched them to 2.5 and the problem went away. it also richened everything else up and the bike is happier on the whole. Im thinking about switching them to a 2.8 just to ensure the float valve isn't acting as my main jet.

My question is; why would they install small float valves? wouldn't you want to have the biggest possible float valve to ensure fuel delivery, and let the jets do the fuel metering?

Doc, where did you find the new ones?  I've had the same nagging issue on mine...too rich one day, too lean after the next change...made me so nuts I put her away for a while....
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on May 22, 2018, 15:56:18
Doc, where did you find the new ones?  I've had the same nagging issue on mine...too rich one day, too lean after the next change...made me so nuts I put her away for a while....

I pulled some out of a set of 29 smoothbores I had sitting around, exact same. Z1 enterprises sells new ones.
Title: Re: saving a 1980 KZ750 twin
Post by: MotorbikeBruno on May 24, 2018, 20:37:28
Rock on, I'll see what's in mine currently and switch them up. Thanks for the info. I do love Z1 :)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 15, 2018, 20:53:12
The forks were pretty soft, so i decided to rebuild them with new springs and try out the emulators. I dropped the fork lowers off to be powder-coated  and despite my CLEAR INSTRUCTIONS they did not mask off the top of the fork tube. I'm pretty pissed about this because I literally wrote  "NO" where I wanted them to mask. They only masked for powder not the sand blasting.  It doesn't seem like the sand blasting got into the tube too far, but it did peel a bunch of Teflon off the bushing at the top of the tube where the inner tube rubs. There is now quite a bit of play between the fork inner and outer at this location. This coated bushing is not shown in the parts diagram, nor is it mentioned in the service manual. It looks like Racetech has a bushing that has the correct dimensions that may work (36x12x2)  I have another pair of forks that I could use but the caliper mounts have been machined on these for my caliper conversion; something I would rather not do again.

how do I get this bushing out? there is very little lip on the backside, probably about 1mm. Also its in there pretty deep, my seal puller won't reach it.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 20, 2018, 03:39:40
through some fugly butchery I was able to extract the bushing. I first turned a 37mm washer that was 1/4" thick. Drilled and tapped that  and flatted two edges so it could be passed though and reoriented to catch the bushing. it pulled out easy. The small bolt is to keep the washer from spinning. just waiting on new bushings and the forks can go back together.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jun 20, 2018, 10:05:21
.
https://www.youtube.com/watch?v=gEGQUgWBQL4
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 22, 2018, 06:13:59
 I got the new bushing from Race Tech. They fit pretty good. I made a nylon plug to push them in because I thought I was going to have to use my press, but i was able to push them in by hand. This made me a little wary because there is nothing holding in the bushing but friction and it went in pretty easy. I have a set of later model forks that have a spring clip to retain the bushing for this reason. I decided to use a spring loaded center punch to "stake" the lip around the top of the bushing to make it harder to back out. I feel better about this. I finished assembling them with new Race Tech springs and gold valve emulators.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 22, 2018, 11:57:45
Looks good.  Love the Racetech stuff. 
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 28, 2018, 05:38:18
So much for my quick top end swap.... no wonder it seemed low on power. The right piston pin was seized in the piston and took a puller to remove. Not sure how it started; further inspection required. the small end of the rod is trashed. Luckily i can remove the rods through the oil pan. but since I have to go this deep I'm wondering if i should pull the motor and go through the whole engine? that's a bunch more work i'd rather not do. There didn't seem to be any big chunks in the oil pan, just a little dirt that fell down when i removed the jugs. I just can't seem to get an easy one on the projects lately....
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jun 28, 2018, 15:11:38
Oh man..  That's ugly.  Maybe it's time for the bigger bore and pistons we've been talking about for a few years?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 28, 2018, 17:27:05
I have 10.5/1 Venolia forged pistons (stock bore), matching cylinder, and a fresh head with a light port and polish, valve job and deck. I was hoping to just swap the top end but it looks like i'm going to have to go deeper.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jun 28, 2018, 20:56:24
Meh, Scotchbrite and a lathe will clean that piston up just fine.  :-*
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jun 30, 2018, 19:09:44
Decided to go all in on the engine rebuild. got some cool mods in mind as well. stay tuned.
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jun 30, 2018, 20:33:22
In a way, I kinda love being forced into a rebuild and bigger bore.  Excuses make it go down easier, and supping a motor up is never a letdown.
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 01, 2018, 20:36:13
Decided to go all in on the engine rebuild. got some cool mods in mind as well. stay tuned.

Right on!.  There's a strong chance I'll have to do the same when I get back into mine.  I look forward to the details of your build.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 06, 2018, 05:35:16
Finally got the easy win I was looking for. New EBC single disk setup. Shaved 4 pounds off rotational mass and an additional 2.5 unsprung with the removal of the extra caliper. I bought a 12mm brembo MC to match. The fitment is super tight. less than 1mm on spoke/caliper and disk/fork leg. I'm digging the new look. Very interested to see how it feels.
Title: Re: saving a 1980 KZ750 twin
Post by: Pete12 on Jul 06, 2018, 08:27:03
Wow, that front wheel looks great, should be no problem pulling that bike up.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Jul 06, 2018, 08:33:54
Venolia pistons - how much ?

My exhaust cam is off to be modded [ remove gear ] and will come back as an inlet !!!

Just waiting to get my new HD compressor and blast cabinet installed - then it's into engine mod mode !  ;D First job is to strip the new twin plug head down and get some blueprinting done. What do you guys use for valve springs ?

There WILL be two donkeys - one will be the Weber / NOS version and the second more long term [ money ! ] will be the blown version. Probably Turbo as the Eaton conversion will rely totally on the good grace of others for machining fab etc.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 06, 2018, 13:20:54
Venolia pistons - how much ?

I got them used from a member over at KZR for $150


What do you guys use for valve springs ?

stock springs. if I had a higher lift cam I would get some custom springs made by Kibblewhite.

Title: Re: saving a 1980 KZ750 twin
Post by: 1fasgsxr on Jul 06, 2018, 13:25:35
Love the new set up.  Looks great.  That's about what I want on the 350F. The stock rotor on it is heavy.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 06, 2018, 14:00:32
Love the new set up.  Looks great.  That's about what I want on the 350F. The stock rotor on it is heavy.
this rotor is about 2.5lbs lighter than the stock single.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 11, 2018, 00:11:30
Small update, but one of particular interest to kz750 twin owners.

I was cross referencing part numbers and realized the z1/kz1000 share the same head studs as the KZ750 twin. This means you can use APE's heavy duty head studs and nuts which are intended for the z1/KZ1000. I have bought a set and can now confirm, however, you do end up with 4 extra studs and nuts you don't need. These bikes are notorious for head gasket leaks, increased compression will likely make this worse, hopefully this will help address that.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 11, 2018, 07:26:03
it begins...
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Jul 11, 2018, 09:21:04
You don't have oil running up and around those studs do you, Doc?  Usually the studs that have the rod between the threads machined smaller than the threads themselves are running through oil passages, so oil flows passed them.  Oil leakage is usually due to the o rings or gaskets that seal between the head and the cylinder.  If that's the case, you're blocking oil passages with those APE studs.
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Jul 11, 2018, 10:45:42
You don't have oil running up and around those studs do you, Doc?  Usually the studs that have the rod between the threads machined smaller than the threads themselves are running through oil passages, so oil flows passed them.  Oil leakage is usually due to the o rings or gaskets that seal between the head and the cylinder.  If that's the case, you're blocking oil passages with those APE studs.

+ 1 I was thinking the same thing. My Honda twin used 4 of the studs as oil feeds and 4 that were o-ringed off. all looked like the tapered one, when you pulled them, the 4 that were feeds came out easy, the 4 that were not were always rusted to shit and stuck.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 11, 2018, 15:41:33
Thanks for the concern guys. If you look closely you'll see there is a separate oil passage on the side that runs up to the head. Its between the outer most two studs, so its all good. Funny enough though, on the z1/KZ1000, oil is fed around the outer head studs as you described. APE mentions nothing about this and I have been running these heavy duty studs in my kz1000 with no problems.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 12, 2018, 03:27:08
Some more info of interest to the kz750 twin owners.

taking from www.z750twin.de/zylinderkopfdichtung.htm


"Only buy the head gasket part #: 11004-1267, the green one
It´s the last and best cylinder head gasket for the 750 twins

A little gasket history :
11004-071 => 11004-078 => 11004-1055 => 11004-1267
11004-071, recall campaign in June 1976
11004-078, the red one with black middle section
11004-1055, light brown, comes with the first LTD model
11004-1267, the green and the best for the last LTD model"
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Jul 12, 2018, 11:49:44
That's great info.  Now I'll have to check and see which ones I have.  Google Translate to the rescue.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Jul 12, 2018, 12:26:23
Small update, but one of particular interest to kz750 twin owners.

I was cross referencing part numbers and realized the z1/kz1000 share the same head studs as the KZ750 twin. This means you can use APE's heavy duty head studs and nuts which are intended for the z1/KZ1000. I have bought a set and can now confirm, however, you do end up with 4 extra studs and nuts you don't need. These bikes are notorious for head gasket leaks, increased compression will likely make this worse, hopefully this will help address that.

Think I'm going to need some of those for the blown motor !!
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 19, 2018, 23:10:11
Finally got around to making mirrors for this thing. I got these cheap mirrors off ebay for $20, they are actually pretty nice, solid aluminum construction and convex glass. I used the old head studs for the stems, turned a little cap where the mirror attaches, tig brazed it on, and polished it back. I also had some stainless flange nuts that I trimmed down so they wouldn't be so bulky.
Title: Re: saving a 1980 KZ750 twin
Post by: advCo on Jul 20, 2018, 00:19:38
Very cool way to repurpose those studs  8)

Not sure whats going on in the sketch in the background but I like it.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Jul 20, 2018, 14:31:06
that's an old painting of mine, as you can see its being absorbed into the scrap wood pile.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Jul 31, 2018, 08:35:55
Help please. I need to know the outside diameter of the front wheel axle sleeve nut.

The guy modifying my Grimeca spindle needs the  measurement. As you know the fork caps have a gap one side when torqued up and I've been given different diameters so far ! ::)

My thoughts are if he makes the sleeve spacer the same diameter as the original sleeve nut - it HAS to be correct !  ;)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 01, 2018, 04:50:54
Im out of town for a couple weeks, let me get back to you when i get home.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Aug 01, 2018, 05:11:49
Im out of town for a couple weeks, let me get back to you when i get home.

You're a star

Cheers

TJ
Title: Re: saving a 1980 KZ750 twin
Post by: der_nanno on Aug 01, 2018, 11:24:54
Think I'm going to need some of those for the blown motor !!

Also make sure you have a copper headgasket made or at least have the cylinder piano-wired.

A Z750 Twin is one of those bikes that have been on my list for a while...
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Aug 01, 2018, 12:29:54
Also make sure you have a copper headgasket made or at least have the cylinder piano-wired.

A Z750 Twin is one of those bikes that have been on my list for a while...

The plan  was for wire ... copper head gaskets are astronomical to have made ! The bottom end looks pretty bulletproof - with some decent rods and pistons ... half way there ! I've secured 3 heads now - so I'm looking at getting a jig set up for twin plug conversions. Not a huge market, but they ARE starting to get popular now. What's donor prices like over there ?
 
Title: Re: saving a 1980 KZ750 twin
Post by: der_nanno on Aug 02, 2018, 02:16:38
Well if you have a CAD-drawing, a copper head-gasket should be within 20 to 30 Euros at my waterjet cutting place. I agree that cometic charge rather handsomely for proper headgaskets though.

Donor prices? Well you wouldn't want to know. 1500 to 2000 Euros, I'd say. It would be cheaper to import them from Germany and go through the legal process. I could probably get one for approx. half the price (and that's including about 200-300 Euros of taxes and fees...)
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Aug 02, 2018, 08:07:18
Well if you have a CAD-drawing, a copper head-gasket should be within 20 to 30 Euros at my waterjet cutting place. I agree that cometic charge rather handsomely for proper headgaskets though.

Donor prices? Well you wouldn't want to know. 1500 to 2000 Euros, I'd say. It would be cheaper to import them from Germany and go through the legal process. I could probably get one for approx. half the price (and that's including about 200-300 Euros of taxes and fees...)

Thanx for the headsup Greg. I could spend months here in the UK just trying to find someone to do the job! I'll contact you nearer the time. Thanx
Title: Re: saving a 1980 KZ750 twin
Post by: irk miller on Aug 02, 2018, 08:24:35
The plan  was for wire ... copper head gaskets are astronomical to have made !

Have you contacted Lani at Coppergaskets.us?  I've never felt his prices were bad.  Should be in the range of $40 - $50.

https://coppergaskets.us/
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Aug 03, 2018, 18:42:31
Have you contacted Lani at Coppergaskets.us?  I've never felt his prices were bad.  Should be in the range of $40 - $50.

https://coppergaskets.us/

Thanx Irk - but carriage from the US is a killer !!! It's approximately TWICE the cost of sending stuff from UK to US. There's loads of bits I want - cheap enough .... until you add in the post.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Aug 07, 2018, 05:28:03
I have 24mm for the OD of the front axle sleeve nut  ??????
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Aug 07, 2018, 21:49:33
i wont be home for at least another week and a half
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Aug 09, 2018, 11:46:19
i wont be home for at least another week and a half

No rush - the machine shop guy is away for a week anyway !
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 02, 2018, 09:21:38
i wont be home for at least another week and a half

Thanx - we took a flyer with 24mm - worked spot on.

re:the APE stud sets - do you think they might be persuaded to sell the 4 studs we need as a kit ? They already make them so would be another market outlet for them !

Work is progressing with the twin plug head conversions - the jig is made [ machine shop ]. I am debating whether to use 10mm or 14mm fo the second plug. Either way the conversions I've seen done so far have left the thread exposed where it follows into the combustion chamber contour - in my view risking a local hot spot .... especially with NOS / Turbo !

The uprated [ 20% ] clutch spring samples are now made - just waiting passivating. I have to get 100 ordered, but that's "only" 25 engines - and I now have 3 !

It would be nice if we could persuade APE to come up with the stud kit. Do you have an address / contact for them ?
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 02, 2018, 17:50:33
You need 8 studs of 2 different lengths. . The 1000 uses 12 studs of three different lengths,  so if you buy the 1000 stud set you end up with 4 studs that are too short. APE might sell you a stud kit, sans the 4 studs you don’t need but demand is virtually non existent for something like this so I would be surprised if they would. You also need their longer head nuts or through nuts to compensate for the slightly longer head studs. Their contact info is at http://www.aperaceparts.com/
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 02, 2018, 18:37:06
You need 8 studs of 2 different lengths. . The 1000 uses 12 studs of three different lengths,  so if you buy the 1000 stud set you end up with 4 studs that are too short. APE might sell you a stud kit, sans the 4 studs you don’t need but demand is virtually non existent for something like this so I would be surprised if they would. You also need their longer head nuts or through nuts to compensate for the slightly longer head studs. Their contact info is at http://www.aperaceparts.com/

Yes, understand re: the lack of a huge market !! - but as they already make the parts ...... worth a try. Thanx for the link, I'll contact them Monday.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 04, 2018, 18:53:25
WOW - result ! I contacted them and they are willing to sell me the parts needed as a kit.

Depending on price I have 3 other people in UK / Germany interested in kits. I'm trying to get an order for 5 kits - then I can ask for discount !

Can you confirm the length [s ] of the studs required ? When I confirm that they will give me a firm price.

Appreciate your help.
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 05, 2018, 01:45:58
Man you keep getting me at the worst times. I just moved at the beginning of the month to a new two car garage. Everything is still packed up at the moment. Its gonna be a second until I can locate the parts. I do remember that the bolts I did not use from their kit were the shortest ones. hopefully i will have a chance this weekend and dig through  my boxes of parts
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 05, 2018, 05:06:51
No rush - sorry to catch you at a busy time !

I'm just glad I got a positive response from APE. In fact they seemed to be quite interested in my project !

Unusual these days for a big company to take time to deal with an enquiry which by no means will lead to substantial orders !
Title: Re: saving a 1980 KZ750 twin
Post by: Maritime on Sep 05, 2018, 08:43:14
But if you give them permission to put pictures on their site etc of your bike with the blower and their studs holding in the pressure that's some great marketing material.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 05, 2018, 09:05:23
But if you give them permission to put pictures on their site etc of your bike with the blower and their studs holding in the pressure that's some great marketing material.

Absolutely MT - they are already interested in the concept - especially for the Cafe Racer market. Might even get some free product !!!
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 20, 2018, 08:05:07
Latest update - APE have agreed to supply special kits to me for the KZ750 twin with ALL 8 studs the correct length.

Is there any reason why the shorter studs and nuts can't also be replaced ?

I'm just working on numbers now to try to negotiate a discount. There are several peeps in the UK and Germany interested - just depends on price - which depends on numbers !  ;D
Title: Re: saving a 1980 KZ750 twin
Post by: canyoncarver on Sep 20, 2018, 11:24:09
I'd buy a set.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 20, 2018, 13:47:03
They'll drop ship for me in the US.

major fuckup with the measurements. I was given 158mm for the outers from 2 peeps - which apparently are in a cross ref: book .... W..R..O..N..G.. They're 180mm.

So have to go back to APE now and look like a dummy fro giving them the wrong dims.

As soon as they confirm they have the 180's i'll get another new price for the set. !! ::)
Title: Re: saving a 1980 KZ750 twin
Post by: doc_rot on Sep 22, 2018, 17:58:17
I still haven't found my engine parts in the garage yet. However I picked up a spare motor today that I broke down last year that has been at a friends shop until now.  I also saw the incorrect stud length listed in the cross reference and knew it to be wrong, but since they are the same studs for the 1000 I figured they would fit.

Stud lengths are 190mm & 180mm
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 23, 2018, 10:19:47
I still haven't found my engine parts in the garage yet. However I picked up a spare motor today that I broke down last year that has been at a friends shop until now.  I also saw the incorrect stud length listed in the cross reference and knew it to be wrong, but since they are the same studs for the 1000 I figured they would fit.

Stud lengths are 190mm & 180mm

Thanx for the confirmation .... reference books eh ????

Good news is I'm getting on like a house on fire with one of the guys at APE and he will sort out a complete set of studs / nuts to suit and allow me to market them as KZ750 twin kit as APE product !! I'll PM you with details.
Title: Re: saving a 1980 KZ750 twin
Post by: beachcomber on Sep 23, 2018, 10:21:22
I'd buy a set.


I'll PM you with details when I have final costs. They will make up a KZ750 twin SPECIFIC set [ 8 studs and nuts ] and allow me to market them as an APE product.