KZ650 cafe-racer

Accelerating pump diaphragm is square. K&L diaphragm corresponds OEM in most respects, except of how it holds returning spring. And here I found a little issue. As you may see, OEM diaphragm has protrusion in its center to hold spring on it while K&L has a bowl for this purpose.





K&L returning spring has larger diameter than OEM spring and it doesn’t seat properly in bowl of K&L diaphragm. I tried to tighten slightly the final round of spring but it did no good. Thus, there is possibility that this “unsettled” spring end may move sideways and damage diaphragm. I decided to not take a risk and used old OEM spring. Later I’ll get it zinc plated to protect it from corrosion.







For covers of accelerator pump and its valve I chose stainless steel Allen bolts with button heads.



Once I finished with accelerating pump I had only one task ahead: to install carburetors top covers. I used the same type of screws, as for accelerating pump, they looks great there.

And sure, here are few photos of assembled carburetor rack. I have to check fuel level and make initial synchronization, but this operation, as well as overflow hoses and air vent hoses installation I’ll do later.

Did you measure float height? I say this because it's normal for the float needle tap on the float to angle downward slightly and yours seem to angle up.

Those carbs look amazing BTW. Well done!

Thank you, Ed!

Both my sets of carburetors have mostly same angle of float tang (as shown on pictures above) that pretty correspond 23 +/- 1mm of float height indicated in 1981 OEM service manual. In fact I set them to 24mm. However, I will check fuel level later to see if it is correct.

While building motorcycle with custom chassis one has to keep in his mind two essential things:

• Front and rear wheels must be positioned inline and centered to longitudinal axis of frame.
• Front and rear sprocket must be in one plane.

For Kawasaki KZ650 cafe-racer I’ve built custom spoked wheels based on Honda CBX550 hubs; I used Kawasaki Zephyr 550 swingarm and 41mm Kawasaki Ninja fork in Zephyr 750 triples. That means the whole chassis setup, including rear sprocket’ hub differs hugely from original. However, I managed to get new wheels aligned with frame longitudinal axis and rear sprocket is located soundly in same plane with its front sister.

It took some time to solve both questions for KZ650 project. However, when one get used for solving such tasks it becomes a matter of thinking and calculation. The crucial point is how to check the result after all parts are ready and all necessary modifications done.

Personally I use Profi-CAT Laser for this purpose. This small tool has flat contact base milled from aluminum and laser leveled with that contact base.



However, firstly I have to assemble rear hub, packing it with new bearing and seal. Then to install sprocket studs and rear sprocket itself:





Now is time for tool. As its counterpart I use old eraser.



It has a flat sides and by blind chance Profi-CAT Laser beam points exactly on edge of white strip that separate halves of eraser with the edge of red point slightly on white. The thickness of white strip is 1.5mm; it makes this eraser very useful in measuring sprockets alignment as it is quite easy to observe any deviation of red laser point from “norm” on eraser.



Thus, the only thing I have to do for checking sprockets alignment is to put Laser tool on rear sprocket and aim its laser beam on front sprocket with eraser placed on its side.



For doing so I used old front sprocket from my supplies (for 525 chain and sure of same thickness as rear sprocket) and old KZ650 front sprocket nut and washer. So just don’t mind the appearance of them, but mind where the point of laser beam is. As you may see, it’s exactly where it should be.

I had an ambition to shoot exploded view of Kawasaki KZ650 engine. To shoot that exploded view I have to put on canvas all engine parts, clean and dry. It’s unadvisable to keep engine internals not oiled. May be it’ll work somewhere in Mojave, but not in Kiev, Ukraine: in long run humidity will make steel parts rusty. So I keep most of engine internals as I take them from engine: even thin old film of oil would keep parts safe from rust for long. My intension was to clean parts right before shooting exploded view of engine and then oil them with new fresh oil. But as it was said: man proposes, God disposes: issues with cylinders and two cylinder heads (if shortly, they all were wrecked during quite a standard works performed by specialized workshops) and upcoming winter made this ambition unattainable goal. So I shoved my ambition where the sun does not shine and used last few relatively warm days for engine parts cleaning.

As it always happen with old engine, I had to play gasoline raccoon for quite a long to get result that satisfied me. I cleaned part after part, then I oiled them with new oil that I am about to use in engine after assembling. After such treatment I packed them in boxes which I protected from dust with stretch wrap:







Units like transmission I put apart before washing them.



The engine, parts of which I use, sat for a long years, thus gasoline, numerous brushes and yet one time gasoline applied under pressure is the only way to clean out dirt, hard particles and other depositions. And that’s why this work must be done on fresh air.

Even as service manuals describe in which order all parts should be assembled, with things like gearbox it’s advisable to place all parts in their “natural” order. However, even if parts were messed, their order still may be “read” from signs of their contact with adjacent parts.

Oiling and assembling:







I did all measurements according to the book and in result I got confirmation that most of parts were not only in specs but in those range that book calls “standard” which means dimensions of new part. The only “out of spec” thing was copper bushing of first gear on output shaft. It’s curios, even taking into account that it’s the largest gear on the shaft of smallest diameter as it means intensive use of first gear. I could only assume that previous owner of engine was learning how to ride bike. However, looks like he didn’t own the bike for a long enough as most of engine parts look like new. And sure, I found and ordered new first gear to get perfect gearbox for my project.

It's time for me to swap out my original tranny for a low mileage one that I have had soaking in oil for the last 6 years .
I was going to just install it but you may have inspired me to do some deep cleaning first.

Thank you for commenting! I just began to feel like talking to meself.

You have all the right measuring tools. Some of those I still need to acquire. I made a career being a Quality Control/Production Manager at a metal fabrication shop. Your pictures make me want to shopping!

Please don't get discouraged, personally during the week I usually check in before work and don't have enough in me to write anything other then "looks great!"
but I do appreciate your hard work and eye for detail, I'm learning from you and so are a lot of other folks, 3000 views and climbing.
Thank you for all your hard work, please keep it going
JD

Rest assured gazz, this thread is being watched closely and greatly appreciated by a lot of members and non members alike. The level of detail and quality work is truly inspiring . Thank you for the time you are spending on documenting and sharing this build.
Jim