KZ1000 Muscle Bike Build - ZRX Swingarm, ZX9R Fork

Had some good time tonight to work on the bike. I started with the shifting linkage. The one I had was too long, so I cut it down on the lathe and rethreaded it:







All attached:



I also spent a lot of time lining up the rear wheel with the spacers I got in the mail today. I ended up removing about .2" from the brake side spacer to take it down to about .8" for the brake mounting surface. I also had to make a small axle spacer for this side to keep the brake spacer from rubbing on the brake caliper. Worked great:



I didn't end up needing to make or modify the sprocket side. I just used a .25" dished 530 sprocket and a .25" spacer to get the chain line where I wanted it. I picked up a 49 tooth rear, matched to a 16 tooth front. I'll admit, I didn't really think this through. Does anyone have any experience with this kind of ratio?

I'll upload more details on the exhaust spacer if there is interest, but I basically pulled out the rubber mounts and replaced it with this:



There is a washer with a nut welded to in on one side, then a spacer with a hole through it on the other. I ran a 3" bolt through the spacer into the captive nut and screwed it all together. I loosened up the middle exhaust clamp, then tightened up the mount. Everything has plenty of clearance now and is pretty solid.

This is how she's sitting. You can see the changed mounting for the tach which lowered it a lot. I'm pretty happy with how it looks. Tomorrow, I'll get the chain on and bleed the brakes, then it is time for a test ride.

So it looks good. There are a couple things to keep in mind with your chain ratio. A stock ZRX1100 with a 170 rear tire is 17:45. So since you are running a 170 rear tire, you have dropped the front sprocket 1 tooth which is like adding 3 teeth to the rear all by itself. Now you have also added 4 teeth to the rear. It is going to be (3.06:1) geared DEEP in my honest opinion. I would have chose a 17:45-47 if it was me. Now if you find the combination you picked to be too deep for your modern tire size, you can pick up an 18 tooth drive sprocket and probable even it out a bit. The 49 tooth radius will help keep the chain up off the pivot from a wear perspective though.

On here is a KZ900/1000 gearing chart from back in the day and the 17/45 ratio was considered hot street.

kzrider.com/forum/5-chassis/270333-kz900-gear-ratios

This was with the larger OD of the original tire and wheel though, so with the smaller OD of the modern setup, you would run a slightly higher RPM for a given speed. Good luck.

Cory

Thanks Cory. I just got the chain on and looked it over. I think the 18 tooth front sprocket is the right path.

I ran into the smallest clearance issue with the chain that will just require a little grinding on a mount, but will require taking the swingarm off. On the plus side, I've gotten really good at it.

Pic of the chain mounted, but with enough slack to replace the sprocket.



I've been buying these offset sprockets from PBIsprockets, and they seem to offer a 16, 17, and 19 tooth. It looks like the 19 tooth will fit, and should give me a drive ratio of 2.57. I think I'll give that a shot.

That should be a nice street ratio. Chris and PBI are great to deal with as well. This is turning out nicely, congrats.

Cory

Awesome build so far, bike sits really nice!

Nice build Johnno,

Having spokes on a fat wheel looks great.
Of course it helps if you have a great example like Cory's build
It is always good to see that people use solutions found on this forum and than come up whit a very personal bike.
Also like the color scheme, is that what you will keep?

Eric

Thanks guys.

Wiers, I've been following your build, really nice stuff! I was always planning on redoing the paint as a part of this build, but the more I look at it the less I want to. The gas tank was repainted in the 80's, and has a lot of nice wear on it that I think looks great. I feel like if I repainted it now, it wouldn't feel like the same bike. So I'll probably just put a fresh coat of black on the tail and side covers and clear coat over the gas tank to seal it.

I just painted the areas where I added metal or ground down the frame, so in a few hours it should be ready for the final assembly.

Its a nice "classic" color and for sure in combination with the black Kawasaki lettering iso the standard white metal logo.
I'm keeping an eye on your build

Eric

Johnno wrote:
I'll upload more details on the exhaust spacer if there is interest, but I basically pulled out the rubber mounts and replaced it with this:

There is a washer with a nut welded to in on one side, then a spacer with a hole through it on the other. I ran a 3" bolt through the spacer into the captive nut and screwed it all together. I loosened up the middle exhaust clamp, then tightened up the mount. Everything has plenty of clearance now and is pretty solid.

great work on the build it is really turning out nice .

i feel like the difference in angle between the tab off the header and your "mid bracket" and the lack of flatwasher under the bolt head is going to cause undo stress on the sheetmetal header bracket possibly causing it to stress and crack it.

i think the easy fix is to tweak your"mid bracket" to match and parallel the angle of the header bracket,then add a flatwasher under the bolt head and then i don't think you'll ever have any trouble with it.

keep us posted,

leon

John,

One quick thing I thought I would mention about the swing arm pivot shaft. It dawned on me as I was ordering my new hardware to mount mine. Do not use any sort of locking compound on the bolt threads you use. This is because you have no way to hold the shaft itself, so it may be difficult to say the least to ever remove it. You must use an external locking method like a lock washer under the head of the bolts that lock the bolt to the frame. I just installed this and they are two bellville spring load locking washers and then I wanted stainless Allen bolts throughout the bike, but anything similar will work. I also threw some antisieze on the threads to prevent any locking together with the shaft. FWIW....

Cory