Nessism wrote: There are float bowl nipples that should have a hose that feeds down to the side of the swingarm, away from the rear tire. The over flow tubes in the float bowl often crack so know that when you are going through the carbs. There is one vacuum line that comes off one of the carbs and operates the petcock. All the other vacuum lines on the carbs are capped off with rubber plugs.

Depending on your airbox, the carb drain hoses could feed back into the airbox instead of down to the swingarm.
If you have a clean air system on the top of the valve cover, then the picture from wiredgeorge shows the correct setup for the vacuum hoses, otherwise three should be capped as Nessism stated above.

Hi,
I have started a build on a 78 KZ650 that was mostly beyond restoration, It was sitting in some over grown weeds for over 10 years. The motor still turns and has compression, The frame, tank and some plastics I can save. The shocks, front forks, wheels and tries are junk along with most of the wiring. I had done a lot of research before starting the work and everything I found on this topic had me concerned, I just wanted to give this bike a new life so I went at it anyways. I picked up a parts bike for cheap, A 2000 YZF 600r for $50.00 that was missing all it plastics but had everything I was looking for. Now this may sound wired but it was nothing as explained, This swap seemed to be easy and that was unexpected. I am a steel fabricator by tread and I do have a full shop to work out of but no machining tools, Hence my concerns. I was able to install the YZF front forks for the cost of new stem bearings as the stems was the correct length. I did a mono shock conversion using the YZF swing arm and shock, The YZF pivot point uses the same size bearing as the KZ and the O.D. of the pivot bolts are the same, I only had to shave a mil. off of each frame boss at the pivot point as the OE KZ swing arm was 2 mil. narrower than the YZF swing arm. At this point I fabricated mounting tabs for the rear shock and set it to the exact angle and location as it was in the YZF and tacked it in place. I no that I need an offset sprocket of about 5/8" to 3/4" and may make something out of some old sprockets to test exactly what the offset is. I had never heard of anyone using a YZF to do a swap like this and maybe I'm the first but it just seemed way to easy and that has made me nervous, I feel like something is wrong. There was no machining anywhere, I didn't even need to relocate the battery. I haven't full welded any tabs yet, I'm hoping someone might be able to either restore my confidence or point out what may be wrong with this build. Thank You for reading and I'm looking forward to any response.

First thing, I'd pull those carbs and break them down. Soak all the hard parts in carb dip and replace all the O-rings. Search the archives for info on all the various O-ring sizes. Don't waste your money on "carb kits" because they are typically full of inferior aftermarket parts. If you need float needles search out some Kester parts or spring the big dollars for OEM.

The carbs have a fuel feed that's between the #2 & #3 carb. There are float bowl nipples that should have a hose that feeds down to the side of the swingarm, away from the rear tire. The over flow tubes in the float bowl often crack so know that when you are going through the carbs. There is one vacuum line that comes off one of the carbs and operates the petcock. All the other vacuum lines on the carbs are capped off with rubber plugs.

Nice work Matt, Did you think at all of putting your painted brake parts in the oven to cure? I always put heads, blocks and brake parts in the oven on low for an hour. I like 250° Turn off oven and let them sit till cool.
And have you though about DOT 5 silicone brake fluid? Does not eat paint.
And I sent you a damper assembly out Friday with 1 st class mail postage. Did not get track # with that.
Post office is playing Political games!!! Wanting a bail out from covid! Really Post office?? You've been losing $ billions for years!!!

I have a side cover coming from Mike in Nebraska. I sent him a pre-paid priority label! Mike did his part great!! Thanks Mike. Last scan was on the 8th. It does say late and behind and in transit on website. But, 9 days? for a 2 pound box?? Wait till the next post office increase for priority mail next year!

I wish those lower legs were here! I can do a nice finish on them. I never did a resto, mine were always highly polished. You should strip the clear lacquer off of them. It will help the next process. I use a spray can of stripper, eats that residue right away.

Keep up the good work. I have another KZ strip beater bike to clean up now! Had ugly spray can paint on everything. I am going to paint the lowers and calipers with real black paint, along with a suzuki GS 1100 swingarm and a set of struts! All black! BBM Black Bikes Matter!

Some years of 550 used 4 bearings and some used 2. You might want to check before you order. (We didn't get the 500 in the U.S.)

I cant tell you info on the swap, but you can compare fastener/bearing sizes on Kawasaki parts diagrams from different models and make your own assessment from that. I can tell you 900cc and larger bikes have larger axles, hardware and bearings (generally). You'll get burned trying to fit things like 900 wheels to a 650 swingarm, etc.

TexasKZ wrote: No need to apologize. It is your machine and your money.

There are many ways to approach what you want. You can go radical with modern suspension and a highly modified frame and a highly modified engine. Twenty thousand dollars later, you will have an old bike that can pretty well hang with some recent 600cc sport bikes, at least until things get really twisty.

On the other hand, you could substantially change the appearance and improve the ride and handling with a minimum of cost and butchery.
How about a front end from a contemporary GPz 1100? Add some Race Tech cartridge emulators and some new springs. Huge improvement.
Add a light weight, but stronger swingarm from a GS 1000, or even a ZRX 1100 and some top shelf shocks. Big improvement.
Remove the touring accessories. Add some lower handlebars. Make a custom seat. Add some rear set foot controls. Huge changes without butchery.
Your bike and money, your call.

If you were proposing chopping up a first year Z1 or an S1, that would be different. A CSR is not rare, collectible, or even special. What you propose is akin to customizing a 1989 Honda Civic.

TexasKZ this is very much in the vein of what I'm looking for. I dont have any problem spending money but I feel those kinds of mods take away from the character of what the bike is and away from the intention of what I'm after. Your other advice is right up my alley and just what I've been looking for. Thank you.

No need to apologize. It is your machine and your money.

There are many ways to approach what you want. You can go radical with modern suspension and a highly modified frame and a highly modified engine. Twenty thousand dollars later, you will have an old bike that can pretty well hang with some recent 600cc sport bikes, at least until things get really twisty.

On the other hand, you could substantially change the appearance and improve the ride and handling with a minimum of cost and butchery.
How about a front end from a contemporary GPz 1100? Add some Race Tech cartridge emulators and some new springs. Huge improvement.
Add a light weight, but stronger swingarm from a GS 1000, or even a ZRX 1100 and some top shelf shocks. Big improvement.
Remove the touring accessories. Add some lower handlebars. Make a custom seat. Add some rear set foot controls. Huge changes without butchery.
Your bike and money, your call.

If you were proposing chopping up a first year Z1 or an S1, that would be different. A CSR is not rare, collectible, or even special. What you propose is akin to customizing a 1989 Honda Civic.

I recently bought a 1981 K1000 CSR. Other than the tires, it's an all original low mileage (for how old it is) bike. Still looks and sounds great. That said, it's a cruiser and not really my style. I want to mod it to achieve old school cafe racer performance and looks. That's where I need help to ensure I'm doing the right things the right way.

A quick history, I have loved these bikes since I saw the original Mad Max when I was 10. The way Toecutter and his gang looked riding through Australia really appealed to my young self. Fast forward 30+ years later and I decided I wanted one of those bikes. I did, what I thought was, diligent research to find out what the bikes in the movie were, about the Airtech fairings, the riders, etc. In doing my searches I saw that although there were different models of the KZ1000, I wasn't reading that there were any fundamental differences in the frame, engine, forks, etc. This lead me to think the only differences were in the appointments like handlebars, fairings, seat and what-have-you. So when my 1981 low-mileage cruiser showed up on craigslist I thought I'd found the perfect bike to recreate what I wanted as a child.

When I first got the bike, given what I mentioned above, I figured all I'd need to do would be the appropriate services, remove the cruiser fairings, change the handlebars, update the gauge cluster, maybe add the Airtech fairings and I'd be golden. Give or take a few things of course. But then I started seeing pictures and videos on the net of how people are currently modding these bikes. I figured that these people were just doing todays version of what riders back in the late 70's/early 80's did to these bikes. I thought maybe that was the way to go to improve the performance and looks of the bike I bought up to a modern standard.

That's where I knew I need help. I've been a car guy my adult life and I needed help if I was going to do any work on my bike right. The first forum I went to seek help was caferacer.net. Being a know-nothing noob those guys quickly brought me down to earth and reset my expectations. They explained that most of the bikes out on the net are more-or-less art projects and not necessarily safe well performing bikes. I didn't explain myself well and I really got some hate from those guys. But I took their criticism and advice and eventually earned a modicum of trust from them. The advice they gave me was to change out the leading axle front forks, triples and swing arm to Z1 pieces, put on superbike bars (I was warned against clip-ons) and some other odds and ends. Or they said I could do a mild front end swap (nothing as intense as a GSXR or R1 swap) and rear end swap along with the other things I mentioned.

So that's where I'm at. I turned to this forum because although those guys are very knowledgeable, that forum is more generalized concerning makes and models. I felt I should seek out some help from KZ enthusiasts. What I'm asking for is advice on how to proceed? How would a veteran KZ rider mod the bike I purchased to achieve that old school cafe racer performance and look? I have no problem doing things affordably or doing the opposite and spending a lot more to reach my goal. Like I was warned, I'm not after a bike that is unsafe and all form over function. I want to do it right and end up with a fun to ride, safe, well-performing bike that follows a function with form philosophy. I take criticism and advice well. I am really here to learn as I've realized I know very little about these bikes. I have to start some place and I figure that's here. Please help me out and thank you for your time.

Thanks again MiKaw and Scirocco.

Have been spending my time getting intimate with a scotch pad and degreaser. It was a couple full days of scrubbing and and cleaning parts. On the upside everything off the bike is pretty close to being ready to put back on. This was also a good way to pass the time while I waited for part orders to arrive.


I ordered a set of carburetor O-Rings from cycleorings.com, which came to just over 20$ after shipping. The set contains jet/drain/plunger rings and has some extras, they fit slide type pre-80s and I can definitely recommend this kit if it fits your bike.
I cleaned everything down and then replaced all the O’s, choke collars, float gaskets, and changed the hardware over to hex heads. Afterwards got the floats adjusted so that the fuel level read to be as close to 3mm under the carb ‘lip’ as possible. Turned all fuel mix screws to be 1 1/4 under light seat as per the manual. Carburetors are finished until the bike is running and I can do a vacuum gauge fine tuning.


For my petcock I did a full O-Ring replacement and solder tacked my cracked primary fuel tube together. The solder would have been a pain to get a full seal so once tacked I used some JB Weld steel stick and formed a thin shell around the tube leaving a little uncoated space at the bottom in case of future procedures.


Pulled apart the rear of the bike, except removing the swing arm, and chased down and eliminated all rust spots on the frame. Have been doing some spot painting to help prevent future rust.


As far as the tear down goes I still need to remove the oil pan and alternator/stator cover for cleaning and gasket replacement. Haven’t attempted the oil pan yet, but so far the alternator cover screws have eluded removal for a couple days now, I soaked several times with penetrating oil, have tapped the screwdriver with a rubber mallet, applied heat via a propane torch all to no avail, not sure what else to do other than keep attacking them, I need to replace the stator grommet/seal as that was leaking in the past. That leak caused a mess of a time under the clutch/shifter cover!!!