1980 KZ650

cdiver666

Active Member
Hi, about a month ago I bought my first motorcycle, a kz650. Since I wanted a bike to work on, (and didn't have much cash) I was looking for an older bike, and quickly heard about the cafe racer thing. I decided to go in that direction because I like the minimalistic looks and the focus on performance.
A pic when I got it:

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I didn't waste any time tearing it apart but first I wanted to make sure I could get it running. The guy told me he would do so before he dropped it off, but he didn't. Oh well. I hooked up jumper cables from my car, and had my brother hold them to the battery cables on the bike (it didn't come with a battery) while I vigorously kick started it. After more than a few tries, it did start and idle. However my brother went inside since it was too loud; I don't remember if I hit the kill switch or if it died when the jumper cables came off. I was just scared the positive lead was going to hit the frame! Anyway I haven't been able to get it to start since.


I originally (and still do) wanted clip on bars. However, the cheapest ones I could find were like 60 + shipping (partsnmore), and the cheapest clubmans were 25 with like 5 shipping (motorcycle superstore was cheaper than ebay). I got those on as a "test fit" and took off the seat, fender, inner fender, and etc. I think I may down the road cut the bars on the ends a couple of inches on each side. The main concern is master cylinder clearance. I was going to flip the headlight ears upside down and try that out but the led signals didn't come with washers and the bolts are too short. So they won't just bolt on. I will deal with those later.
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I originally wanted to use the stock foam and pan and shave off the second hump to make it look like a solo seat. However the frame was in the way, and the sewing machine broke while trying to make the cover for it. So I said, screw it, I'll shoot for a real cafe seat.
Using part of the stock pan and some sheet metal I started to make a seat. It bolts right to the frame where the battery box used to. I am trying to make the rear hump out of sheet metal. Like a regular curvy type. It is difficult. I can't much continue on that front however since I ran out of welding rods. I do plan on bondoing it smooth.
On a side note: I recieved a craftsman arc welder for Christmas and have been using that, however it burns through the metal extremely quickly and is very difficult to get it to arc. I had no trouble on the arc welder in school, but this one is hard. Maybe I'll switch to a cheap mig? Opinons please.
Here is the start. I have more pieces that just bolt on so I can mock it up quickly, but without the rods I can't do much.
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I also bought led turn signals on ebay (19 with free shipping) and a 50 volt 10,000 uF capacitor. I have not been able to get the bike to start with the capacitor, but considering how difficult it was to start before, I don't think thats much of an issue.


Here's where I cut the frame. This piece will be angled up about 30 degrees to allow tire clearance. The regulator, capacitor, and kill switch will be relocated under the seat. The power will run right from the capacitor to the coils with the kill switch in between. I will be removing the electric starter, and re-wire the whole bike. Oh, how hot does the regulator get when the bike is running? If I were to stick my hand under the seat to hit the kill switch and I accidentally touched the regulator would I get burned? I could make like a guard if thats the case.
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I think I want to take off the front fender as well, for looks. However, having never ridden a motorcycle, does anyone think the fender protects you, the rider, from kicking up rocks and such? I do plan on having a full face helmet. Spring is a ways away up here so I don't have any riding gear yet, but I will.


Last night I got the carbs off (what a pain in the ass) and am going to clean those up. The bike didn't come with air filters, so I plan to get the emgo pods from z1.


Here it is torn down. I don't want to get into the engine until later down the road. I want to have it ready for spring. But down the road (once I can afford it) I would like to do an 810 big bore, with stock heads and jugs. (with 750 sleeves).
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Here are the carbs, I have never cleaned carbs out before but I'll see what I can do. Any suggestions? Please let me know. I won't be cleaning them in the house by the way. I was just looking at them.
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The bike came with just about all stock parts, and I won't be using a lot of them. If you need a part (like battery box, side cover, stock turn signal) let me know I'll let it go cheap or trade for something aftermarket.


A concern at this point is the coils were not both the same. One looked stock and bolted to both holes, and one was larger and was only bolted to one (since the other didn't line up). Would I be okay to go with dyna coils at 3 ohms and then likely upgrade to dyna s electronic ignition later?


Well if you managed to read all of that (or just looked at the pictures) please tell me any comments or suggestions. This is my first motorcycle, and first motorcycle build. Thanks
 
Looking good, the KZ650 is a nice bike for this sort of thing and actually took out a bunch of speed and endurance records in its day. Not a bad base to start from at all.

On the carburettors, you will want to pull the bottom covers (float bowls) and check them. I would have some fine wire/needles, cotton-tips, rags and denatured alcohol standing by so you can clean everything. Worst case scenario is that you'll have to pulll and clean a few jets, as well as buff crap off the inside of the bowls. Best case scenario is that they're not too bad inside and you really don't have to do much.

You may want to consider buying stainless hex-heads for replacing the original carburettor screws. Trust me, it'll be the best $5 you've ever spent, as the stockers strip like nothing else.

Your idea for replacing the non-matching coils with Dyna 3ohms sounds good. Make sure you have good sparkplugs (I like NGK-R's) and leads, too... assuming the coils don't come with any leads.

A word on pod filters - you will need to rejet you carburettors. I'd start out 2 to 3 mainjet sizes over stock, and at least one needle notch down (needle height raised by one notch). You may also to adjust the pilot jet upwards by maybe one size. Hint: If you need to apply constant choke to get the bike running well its lean, so you need bigger jetting.

What you've outlined will give you the basic triangle for a well performing bike: Fuel, Air & Ignition. Once you've sorted those its much easier to rectify any problems you might have.

Cheers - boingk
 
Yeah replacing those bolts sounds like a good idea. It seems like all the bolts are philips heads, and more than a couple are stripped already from the PO. I did take off one of the float bowls already and it looked pretty clean. The floats are a black material, so I was wondering will the carb cleaner damage that? Well I guess not since gasoline doesn't. I heard to keep it away from rubber though.

I was hoping they were already jetted up since there was an aftermarket exhaust and no air filters when I got it. I'll check the jet sizes and find out what the stock ones are.

I would like to buy the coils and spark plugs and wires before I try to run it again, but if I don't have the cash by the time I'm done cleaning the carbs and re-wiring the thing I may try to work with what is there (and replace ASAP). The bike has run once after all. I hoped to re-use the stockers since 130 seems like a lot for this cheap build, but since they aren't the same I changed my mind.

Oh my plan for the exhaust is to use the same header pieces painted with header flat black, that go 4 into 2 into the hedman "hot tips" exhaust tips. They have like a red resonator built in that I think looks cool and hopefully is enough to satisfy NY state requirements. The government website was pretty vague, probably on purpose.
here's what they look like. I think the short chrome tip on the end of the flat black pipes will look cool.
http://www.race-mart.com/Hedman_Hedders-HED-17120.html
 
Nice find, I love KZ's :)

The KZ carbs are dead simple to work on, but post any questions as you go through them. Let us know what the jet sizes are in there now. I used the Emgo pods on mine with a mildly modified stock exhaust. I went with a 17.5 pilot but can't remember what I bumped the main up to. I'll check it out and let you know. Once you're finished cleaning the carbs be sure to check/set the float levels as well, and then sync them up once you have the bike running. Makes a big difference.

Best of luck. I'll be following.
 
welcome. You'll find theres plenty of kz650 build here, another one is always welcome. you mentioned you were in nys, so definately check out http://www.z1enterprises.com/ they're very helpful, and have a lot of hard to find parts.
 
29 palms I have read your thread and it seems that we're in practically the same boat, being first time motorcycle owners of kz650s. I'm near Buffalo so Z1 is like an hour and a half from me. Where are you located in NY?

Still need a center stand? I have a center stand on mine that I would be willing to part with if I can make a motorcycle stand out of some metal I have. I'm not sure if it would be strong enough though. I'll let you know how that goes.

I got into the carbs a bit more, and number 1 bowl looked fine, then number 2 was terrible. The PO said that one had trouble, and I can see why. I haven't used much carb cleaner yet. I'm not looking forward to it since I want to use it in a "well ventilated area," or my garage with the door open, and its really cold. That will have to be in the day-time.

I'm going to try and get the starter off. lets see how that goes.
 
Looks cool! The starter is super easy to remove and gets ride of the big relay as well... Then you can go with smaller wiring and smaller gel battery :)

If you find a handy solution to plug the starter hole in the case post it up! I'm looking too... I had my bro machine a plug out of aluminum that he just shipped to me - hopefully it works. I'll post pics once I get it and install it.

My floats and bowls were a bit messy too... I'd also check your overflow tubes while you have the carbs off and open. For some reason they are prone to cracking down the length of the tube. I couldn't figure out why mine was pissing fuel all over the floor once I got it all together... alas.... cracked tubes.

Good to see another KZ! Good luck and keep the updates coming!

Cold weather is keeping me from working on mine so I have to live vicariously through others :)
 
I was thinking the same thing. First bike as well, I've never rode one yet. I'm in Rochester.
Don't plan on going to Z1 they don't really have a store like I thought they did. I was still able to talk to some very knowledgeable people who got me all the parts I needed with out the shipping costs.
make sure you re-jet the carbs when you have the float bowls off if you plan on using headers. I used 110s, as that is all you need unless you want gobs of power. I opted out of that being my first bike and all.
I'm not in need of a centerstand anymore, I'm pretty sure it won't fit with the headers im going to use now, but thanks anyways.
 
The starter wasn't bad, I just had to yank like hell on it. I kept checking, did I get all the bolts? But it came off eventually with a little "coaxing." I also took off the front fender, I'm not sure if I like how it looks. With nice tires though I wouldn't mind it.
I think I will take off the center stand anyway for looks mostly. Hopefully a stand would serve the same purpose, since I would only be working on it in the garage, where I would have the stand. I think I can make it with what I have but I need the welding rods... and some wheels from the hardware store.
As for plugging the starter this video gave me an idea, it shows it 30 seconds in:
KZ 650 Cafe Bare Bones
What it looks like he did is drilled and tapped the hole, then made a disc to cover it. As long as there is nothing behind there that would work but I don't know. I would take a picture of where the hole would go into, but as you may have noticed I don't have a real camera, just an old cell phone.
 
The starter hole is about 48mm ID (IIRC) ... what I think he has done is used an expandable rubber type plug. I'll bet that wing nut on the outside pulls a plate on the inside to squish a rubber plug tight against the ID of the starter hole. Cheap and easy for sure....

All you need is something to keep the oil in the engine and the crud out - As long as your crank case vent is clear and functioning properly there will be minimal pressure building up.

Here's a pic of the starter hole:

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I think you're right about the expanding plug thing. That would probably be the best way to do it. Here's a thread from KZrider that has a picture in it.

http://kzrider.com/index.php?option=com_kunena&Itemid=116&func=view&catid=4&id=361901

On the jets in my carb I'm pretty sure I could make out 112.5. One jet and the float bowl were covered in this green shit (the carb the PO said was backfiring or something). The float would stick as well on that one. The jets have a small rubber thing that seals it on. On the dirty one though it was all cracked and fell apart. Could I replace that with a small o-ring? It won't seal without it. The spray cleaner took care of the bowl alright but not the jet as much. I think I'll try soaking it in lemon juice. The floats were decent but could be better, I think soaking would do the trick. I'll worry about changing jet sizes later.

And has anyone used the passenger pegs as the rear set location? It seems pretty comfortable just sitting on the bike like that. I'm pretty tall, 6'1'', and it felt alright. It did feel like the pegs could be lower though, but then again I don't have any foam mounted on the seat pan I was testing with so that could help out.
 
I soaked the problematic parts with a mixture of lemon juice and carb cleaner and that took care of the remaining grime. I re-assembled them but I still need an o-ring for one jet. Z1 has one for .50 cents but I'll see if the hardware store has one that will work.
I have 112.5 mains and 15 pilots.

I was wondering if anyone knew how I could get 18 inch spoke wheels on my 650? I'm not sure what models came with them. Didn't the older kz650s have 18 inch spoke fronts, but 16 rears? I want 18s all around. I would like to keep single front disc and rear drum. I understand kz1000 will fit with swapped bearings. I'll keep looking for information. If you have spokes I would be willing to trade my mags!
 
Hey man,
I realize you're looking for 18's front and rear but if you have to make a compromise my '78 KZ650B has 19" front and 18" rear spoked wheels... single disc up front and drum rear. Maybe you can find some on Ebay or pick up a non-runner for parts?

Have you pulled any cleaning instructions from the net to get all the small passage ways clean in your carbs? If the mains are plugged you can be sure the idle and pilot circuits will be plugged as well and it will never run right if you don't get them really clean! There is a ton of good tips over at the kz650.info website.
If you've already done this just disregard my jibberish :)
I went through the same ordeal on mine.....
 
Hmm, I didn't know that they had 18/19s. Maybe I can use a kz650 rear and modify some other front from a different kz, since width wouldn't matter as much. My budget is basically $0 for now though so wheels are low on my priority list. I do really like the look of having the same diameter front and rear wheel, so I'll be on the look out for a way to adapt an 18 on the front.

As for instructions I read a word document I downloaded from kzinfo that was very detailed about cleaning the carbs. I didn't really do much honestly though, since the PO had drained the carbs and they were very clean with the exception of one float bowl. I just sprayed carb cleaner all over the place and they look alright. My main concern is electrical now, and getting the bike at least running. I know it ran once... and today was almost 60 degrees!

I'm re-wiring the bike with bare minimum wires. That does include turn signals though here in NY. I am going to mount the capacitor, kill switch, fuse box, and regulator under the seat. In order to hide everything, provide some water protection from the wheels, and make it (hopefully) look neat I'm putting everything in a metal tray:
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Everything is tight in there but I think I can make everything fit, and hopefully it will be hidden from view by the frame. Only thing is I need to add a fuse, maybe I'll just cut up the stock box. The switch will be the main kill switch and stick out the back. I don't plan on running an ignition lock cylinder, the power will run right to the coils and headlight from the capacitor. Maybe I will install a dummy lock cylinder though to confuse potential thieves. Does anybody chain their motorcycle up or anything like that? Should I be worried with only a switch? It will be out of sight.
 
I have a kz550 and I'm doing a dual disc swap. I bought a 78 kz750 dual disc mag wheel and I just have to buy 550 bearings and swap the axel from the 550 mag to the 750. The axel on the 750 is larger but the outside diameter of the bearings are the same, inside diameter of the 550 is smaller. Maybe it's the same on the spoke hubs. Hope that helps
 
Wargo, yeah I heard similar things (about swapping bearings) to put kz1000 wheels on the 650.

I just painted the electronics tray. I may use the same paint to do the tank, it looks pretty good. I haven't looked at it in the sunlight though since its still drying so I'm not sure if I would want it on the tank. It is a flat black. The headlight bucket is rusting a bit so I will probably paint that as well.

I also bought SPDT switches from radio shack that I will be using for the headlight and turn signals. They feel kind of cheapy, not as good as the SPST I had already for the kill switch. I am worried about how they will hold up if they get wet. I guess time will tell.

I also took off those really skinny wires of the capacitor and the kill switch and soldered on 12 gauge instead. I will be wiring that into the bike later tonight after the paint dries. I have the headlight switch soldered to be on high, low, or off, and I will do the turn signals later. I think I'll run the power through the relay and then to the switch. That makes more sense for the front signals. I don't have an electronic relay yet though. I don't have a headlight bracket yet so I haven't got the signals on physically. I may make a z1 order and get them, since they have ones I like for 9 bucks. I need air filters and coils from them as well, but I don't have the cash for those.
http://www.z1enterprises.com/detail.aspx?ID=431

Unfortunately I took the seat apart because the weld was terrible. To prevent from burning through I turned the amps way down and it didn't penetrate at all. I tried welding it again, but it just burned through. Arc welding isn't the way to go to weld thin sheet metal to thicker metal. I'm not sure how I will make the seat cowl now. Maybe I can try to make it out of one big piece of metal. Fiberglass isn't an option at this point because of cost, but I may end up going that route later (if I can't make the metal work).

Since I only have the kill switch to turn off the bike, I think I'll use a U lock and maybe a disc lock for the front. I'm not worried about theft from my home, since we live in the suburbs and it will be in the garage, but I would be worried about leaving it on campus and such. I may get a cable and lock it to something, but I'll worry about that later. Now my priorities are to get the electronics sorted, get it running, and then worry about the seat cowl. I'll get some pics of the headlight bucket and the electronics tray later.
 
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Now I just have to attach it all to the bike, and figure out a way to mount the turn signals, since they hold up the headlight.
 
I just did a similar thing on mine this weekend... toggle switches on the bucket and a main disconnect for the battery to eliminate the keyed ignition switch. I kept most of the main harness and just tied some wires together and routed others through my toggles. My main disconnect is facing down from my electrical pan under the seat. I left the keyed switch in the bucket as a sort of decoy.... as far as signals are concerned, I'll be drilling a new hole on each side of the headlight ears and putting in a small LED type signal and will do the same in the rear - either directly onto the seat or at the gusset where the rear shock mounts.

Don't 'cha just love playing with electrical!


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sbruton, yeah that looks very similar. I think I will do the same as what you said to mount the signals, since their bolts aren't long enough to mount the headlight itself so I'll probably end up using bolts and huge washers. Thanks for your pictures. It looks like you did it "right" since you used connectors on your switches, where I just soldered them in. Where did you get your switches? I am not very happy with my radio shack ones. So one switch on yours controls one turn signal? I like it. I think I will mount an ignition cylinder in the bucket if there is room to fool potential thieves as well.

So on my Craftsman Arc welder, there is a dial on the front to adjust amps. I turned it down to weld sheet metal before, but I thought there were like 360 degrees between high and low. Since I didn't see any gauge (there isn't one on the front) I didn't know any better. But then I saw on the top a little bar that shows what amps you're at. I had to turn the dial a LOT to lower it significantly. I was at max (90) before, so I turned it down to 40 and man is there a difference. I can weld the sheet metal together now. So the cafe metal seat is back in business!
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I re-attached the angled piece to the bottom, and then attached the top piece. I'll add the sides tomorrow and I'll be in great shape!
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Here's one of the weld between 2 pieces of sheet metal. Not great, but I'm pretty pleased considering the performance before. I still can't run the bead very far before it gets to hot, and it is difficult to get it to arc, but its way better than before.
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I more or less had nothing better to do, so I sanded the tank and rattle canned some flat black on. I started a layer of clear over it, but the can was running out and it was like splattering. So I just put another layer of flat over it. So there is clear, just underneath the black.

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Here it is on the bike

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Sorry for the quality, all pictures were taken with my 2 mg, 4 year old camera phone. My real camera broke awhile back, and my sister lost the cord for hers.


I found a helmet on craigslist for $15. Its 3/4 style with a face shield. I bought it, and am very happy with the fit, and mostly the price. It is black. I am tight on money so it will work well until I can afford to buy a new full face helmet. Ah, what the hell, here's a pic:

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There are 3 toggles on my headlight bucket...
1.) Ignition/ main power
2.) headlight on/off
3.) Power to dash lights and hazard/ signal lights

The 4th toggle I have tucked under my seat is the main power disconnect.

The reason for all the switches is, with running kick-start only I wanted to be able to kill most of the lights to give full battery power to the ignition system. I am only running a small 5Ah gel battery so I don't want to kill it prematurely....

I picked up my toggles at Napa...I'm sure any auto store will have them.

Looks like things are shaping up for you! Keep it up... it won't be long before you're on the road.
 
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