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Author Topic: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)  (Read 22302 times)

Offline hallin222

  • Posts: 163
  • aka: HonkyKong
    • HonkyKong Customs moto-art
OK, so after much harrassment from others, I finally decided to start a build thread for the project bike I've had for about a year now.  Progress was delayed for much of 2011 due to shoulder surgery, but I'm back now, and the KZ is coming along a little better now.

Back story: a year or so ago, I helped a friend transform his 1976 CB750K from stocker to rocker (see pics below) and had so much fun, I wanted to work on a bike that I actually got to keep when I was done. 







For MY bike, I kind of wanted a vertical twin, but needed to build a bike on a very tight budget, so Triumphs and Nortons were not an option.  Even XS650's seem to go for big money in the Austin area, so those were out as well.  I'm also a bigger guy (6'3"), so smaller twins (CB350, 400, etc) would just look silly with me aboard, so my search began for a big Kawasaki twin.  I fell in love with the Wrenchmonkees stuff and saw what was possible with them, so I scored a junker for a few hundred bucks.  Nasty, huh?





Ugh.  This is how I received the rest of it.



I won't bore you with most of the teardown photos, as you're all familiar with the procedure, and they were for my own reference anyway.  It didn't take long for it to end up like this.  Tail cut, de-tabbed, and passenger peg / exhaust hanger brackets hacked off.



More to come......

« Last Edit: Jun 10, 2012, 21:10:21 by hallin222 »

Offline hallin222

  • Posts: 163
  • aka: HonkyKong
    • HonkyKong Customs moto-art
Re: Project: "HonkyKong" 1979 KZ750B Twin (brat-tracker-thingy)
« Reply #1 on: Jun 09, 2012, 19:36:04 »
Knowing I had lots of parts to strip and re-paint on this project, I invested in a cheap Harbor Frieght sandblast cabinet and went to town.  I few other friends have build projects going on too, so I knew it'd get used enough to justify the expense.  Lucky, wifey is pretty accepting of tool purchases, seeing them as long-term moeny savers, allowing me to do more myself, rather than paying others to do it for me.

Just some of the parts that got sanded and/or blasted and re-painted:



This engine is actually from another parts bike I picked up for free, if I remember correctly.  It's from a 1980 KZ750G, and looked to be in better shape than the 'B' model's gas burner.  I had it running on one cylinde prior to cleaning the carbs and acquiring a new coil, so I'm confident it will serve me well.




Offline hallin222

  • Posts: 163
  • aka: HonkyKong
    • HonkyKong Customs moto-art
Re: Project: "HonkyKong" 1979 KZ750B Twin (brat-tracker-thingy)
« Reply #2 on: Jun 10, 2012, 01:11:40 »
Here are some bad cell phone pics of my first idea of seatpan and rear hoop.  It was taken from the rear of a 1980 KZ750 (4 cylinder) that a friend of mine is hardtailing.  Luckily, the width was the same as my frame, 'cause he had a hell of  time trying to bend two identical 90 deg elbows with a cheap hydraulic pipe bender.  A 180 'U' was going to be impossible with our tools, and this fit pretty well, so I took the cheap, easy way out.   The low res pic is probably a good thing, so you can't see my horrible welds.  No worries, though.  I smacked it with a mallet several times to test its strength, and I'm able to lift the entire rear of the bike (with engine, forks, swingarm, and wheels installed) from it without trouble.



Yes, this is ugly, but my borrowed MIG had a less than predictable feed, and this was my first real attempt using it.  Since its not really a load bearing section like the neck, engine cradle, or triangulated rear section, I'm not too worried about it.


Eventually, that section looked like this, after a small filler section was added from a wedge cut from a junk handlebar, then ground, bondo'd, and sanded smooth.



WARNING: Firestone Alert!  Haters gonna hate.  I still dig 'em.



My first loose roller mockup.  The new bearings (wheels & steering neck) have yet to be installed in this pic, but it was more to get me motivated to keep working once I saw what looked remotely like a motorcycle again.  The bars are some aluminum Renthal MX bars I bought as a pile of parts from a guy, who also provided that front Firestone.



« Last Edit: Jun 10, 2012, 09:42:38 by hallin222 »

Offline hallin222

  • Posts: 163
  • aka: HonkyKong
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Re: Project: "HonkyKong" 1979 KZ750B Twin (brat-tracker-thingy)
« Reply #3 on: Jun 10, 2012, 09:41:53 »
The next step was to paint the frame, install new bearings, and get the engine re-installed.  Big thanks to my buddy, John, for helping with that step.  Lifting a big twin into a freshly painted frame is not something I would have wanted to do with only two hands.

It's starting to look like something now.  Those pipes are actually off the same 1980 KZ750G that I lifted the engine from.  I wanted the disc brake rear end of the "B" model vs the drum of the "G" model, so the swap of everything was necessary.  I could have just swapped the rear wheels and swingarms, but the '79 "B" frame also has that rear master cylinder mount, seen in the front of the main triangle, that I didn't want to have to cut and re-weld, so I kept the '79 frame.

I'm not sure that the 18" cast rear wheel was stock on this bike, and it may have been transplanted from a KZ1000 or something, sometime earlier in this bike's life, but I'm not sure.  I'm still having slight rear wheel alignment issues, so it someone can explain (or provide measurements for the) stack up of spacers on that axel, it would be greatly appreciated.



It's not really visible here, but currently my wheel is sitting a little left of center, which I had to do to get the rotor bolts to stop rubbing the inside of the caliper mount.  I still need to figure that out.  My parts diagrams don't exactly represent the collection of parts and spacers that my bike has, which led me to believe that rear wheel was not stock.



Also notice my paper mockup of my proposed underseat electrical tray.  I took some manual measurements, modeled it in SoldWorks, then printed a 1:1 flat pattern to cut out and fold up before trying it with sheet aluminum.


Offline hallin222

  • Posts: 163
  • aka: HonkyKong
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Re: Project: "HonkyKong" 1979 KZ750B Twin (brat-tracker-thingy)
« Reply #4 on: Jun 10, 2012, 15:53:43 »
Here are a few shots that are chronologically earlier than those posted above (notice no carbs or pipes installed yet), but are a little clearer and provide more info about the overall stance of the bike.  The 2nd image, in particular, makes the entire bike look taller than I'd like, but without the full weight load (of both the missing parts and rider), and the lack of pipe running under the frame to fill that frame-to-ground space, I think it's just an illusion.  The addition of more parts and pipes in future images make the bike look lower than that, which I prefer.





This is why I can't ride small bikes.  With the frame cut, I'll be using 90% of what's left of the seating area.  I assumed as much going into this, which is why the rear peg mounts were some of the first things to be cut from the frame.




Offline sinbad85

  • Posts: 329
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #5 on: Jun 11, 2012, 09:34:45 »
sign me up!

Offline hallin222

  • Posts: 163
  • aka: HonkyKong
    • HonkyKong Customs moto-art
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #6 on: Jun 11, 2012, 23:32:13 »
sign me up!
Alright, sinbad, it appears we have a little Kawi 750 twin build-off brewing here.  :-) Unfortunatley, I'm way behind you, and starting with a much rougher doner, but I'll do my best with what I've got.  Stay tuned, and chime in with advice anytime.

Even pushing this bike around the yard, the forks feel WAY undersprung.  If anyone has a suggestion for this in the way of stiffer donor springs from another 36mm Kawi fork, please let me know.  At my weight, I'll want something stiffer, especially with the bike lowered a little, like it will likely be when completed.

Offline hallin222

  • Posts: 163
  • aka: HonkyKong
    • HonkyKong Customs moto-art
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #7 on: Jun 12, 2012, 00:10:01 »
Exhaust chopping time.  While these 1980 KZ750 G pipes were in pretty decent condition, I just wasn't loving the long, stock look, and knew I didn't want a stock sounding bike when done, so I scored these Harley mufflers off a 1999 FXDX Super Glide Sport in trade for a 6-pack of Shiner.  They were even pre-cored of their restrictive factory baffle via a hole saw, and while still filled with the larger diameter, perimeter baffle, you can look right down through the 1-3/4" center of these.  I actually owned a '99 FXDX back in '99-'00, before buying the 2000 version of the same bike (which I still own today).

Stock Kawi pipes:


Closer:


H-D mufflers installed, after cutting the header pipes just ahead of the stock crossover tube.  I hope the removal of that crossover doesn't give me difficult tuning issues later, but I'll figure it out.


Other side:


Closer:


The fatter muffler section meant that the exhaust could now longer be run along or near the same vertical plane as the lower frame tube.  My first solution to this (starting on the  right side) was to rotate the header pipe outward, allowing the short, fat muffler clear the frame tube to the outside.  All was well, as it still cleared the kicker arm through its full movement, but this solution was not viable on the LEFT sie of the bike due to the kickstand bracket.

The new solution was to use the same header pipe rotation, but now to the INSIDE of the lower frame tube, placing both mufflers tightly under the bike slightly, for what I found to be actually a very cool look, although subtle.

Right:




Left:


Rear:  I love this shot, and the narrowness this creates.


These were just clamped on loosely, requiring some High Life can shims to get a tight fit to the headers.  I still need to fabricate a sheetmetal bracket to support the rear of the mufflers via the H-D carriage bolt and slot mount, and some rubber-coated P-clamps that I'll be hanging from the horizontal frame tube just behind the oil pan.  I removed the stock centerstand brackets when hacking other bits of this frame last summer, so they're no longer available for use in that regard.

Area needing the custom bracket.  Note the tight clearance to the frame tube and oil pan.  The P-clamps are not shown, but you can see where they'll be going.  With some black paint on it, that bracket should mostly disappear from view, giving the mufflers a clean look, without excess clutter.


I think this muffler solution also give the bike a little lower look by filling the empty space under the frame.  I'm happy with it, and for the cost of a 6-pack of beer, I couldn't be happier. 


 

Offline sinbad85

  • Posts: 329
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #8 on: Jun 12, 2012, 03:46:00 »
exhaust looks good dude....

apparently removal of the link pipes slightly reduces torque...... i did it however and didnt notice much loss at all....
these kz's have stump pulling torque anyway.....

haha bring the build off on!!!
i dont plan on having mine finished within six months though.....

good luck on the build dude! ill be watching......
and using yours for inspiration too!

Offline tron97

  • Posts: 184
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #9 on: Jun 12, 2012, 03:58:54 »
Loving it so far. Im tunin in

BBBBRAP!

Offline hallin222

  • Posts: 163
  • aka: HonkyKong
    • HonkyKong Customs moto-art
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #10 on: Jun 13, 2012, 01:28:18 »
Custom fork brace pics below.  Note that I didn't create this from scratch.  The dual arch brace was acquired along with a bunch of other parts, many of which came off 70's era enduros, I think.  This was just too cool of a piece not to use, so I made that center rib from a chunk of 1/4" aluminum plate, that was then rolled (via the help of fresh_c) to the approximate radius of the tire.  I tapped the two mounting holes for metric fasteners for bike consistancy, then drilled it full of holes and sanded it smooth for asthetics.

However, the pre-existing fork mounting hole locations and side plate width didn't exaclty fit the KZ forks, so I cut up some side plat spacers (barely visible in pics) out of 1/4" aluminum plate on each side.  Also, with the 1/4" strip now mounted UNDER the arches (which I love the look of), the center rib grazed the tire slightly.  If that happened when stationary, It would cause a problem at speed, so I slotted those holes with a round file to allow the assembly to sit a little higher off the tire.  I hope there is enough clearance.









It's a pretty close fit here.  Should I have any concerns about tire 'growth' at speed?  Also, ignore that ugly right fork leg.  It will get sanded down before this project is all done.


Feedback is welcomed.  Keep it coming.  I have a few stylistic ideas for this bike, but am open to suggestions.

Offline sinbad85

  • Posts: 329
Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #11 on: Jun 13, 2012, 07:59:47 »
wholly shit dude that is one AWESOME looking fork brace!!

just dont plan on going riding in the rain.....(although we never actually "plan" riding in the rain now do we?) haha

well done!
i was going to bend something up out of some 8mm or 10mm steel rod. but i dont think it will look anywhere near as good as that!
has certainly given me some ideas!

the only thing ide be concerned about is the clearance... at say 80mph or above the tyre is going to have a massive amount of centrifugal force on it thus trowing the tyre out.....
just hope it dont rub!!


Offline hallin222

  • Posts: 163
  • aka: HonkyKong
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Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #12 on: Jun 13, 2012, 11:15:08 »
It's been brought to my attention via PM that this is not the world's stiffest design, as it's more of a fender mount, really, which I'm aware of.  It'll never behave like a true brace, and I'm ok with that, considering I was going to run no fender or bridge of any sort until I stumbled across this part.  Honestly, I just think it looks cool.  There is also the possibility of me raising it of the tire another 1/8" or so if absolutely needed, but there is no need of running it 1-3/4" off the tire as was suggested via PM.  No STOCK fender even sits anywhere near that high.

Perhaps I should have called it a "custom decorative fork treatment" or something more appropriate.  This was done 90% for asthetics, rather than performance.  I'm not looking for the fastest, best handling, best braking bike here, just a fun, cool looking cruiser that I'll be proud to have built myself.  If I were after all-out performace, I wouldn't have mounted up those Firestones, or chosen a heavy 30+ year old motorcycle as my foundation.

There is also concern (from others) regarding the lowered forks.  While I may lower it 'properly' via shorter, stiffer springs, the ride height viewed here isn't that low and has no frame or header clearance issues with the front tire.  I would like to stiffen the front end though, so if anyone knows of another model's springs that might fit my needs, please chime in. 


Offline JRK5892

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Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #13 on: Jun 13, 2012, 14:31:31 »
really a good looking build so far
Joe
"your life is an occasion, Stand up to it"
www.thepowderpro.com

recent builds: Hd street bob, TX cafe, KZ bratt, Goldwing tour, bratt wing, st fighter, road king, vriago bobber, chop, FXD, 1200 sporty, 1200xl sporty, GSXR, Royal enfield.. and more

Offline rays650cafe

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Re: Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)
« Reply #14 on: Jun 14, 2012, 00:42:12 »
Seriously good stuff goin on here. I have concerns about your fork decoration being so close to the front tire. I don't know ya, and it wouldn't concern me as much if it were over the rear tire. But I have been over the handlebars at high speed. It sucks. I got lucky,me and my bike landed in the soft stuff. i just hope you reconsider the extra 1/8 inch before you "see" if you need it. Guessing those old school tires grow at speed. If it were the rear tire in question, I figure it would just flat spot at worse,add a little excitement to your ride. Thats the front, That could ruin a tire and a pair of underware. Just my .02 nice build,good riding.
High functioning sociopath.