Problems getting Police 18" Rear to fit KZ1000A2

I read about this swap, but now cannot find where I originally got the information. I'm trying to put an 18" rear on my KZ1000A2 which had, had a 16" Lester rear fitted. I had everything measured up and thought it would go right on, but hit some snags when I tried to get it together today, I wonder if someone who has actually done this could help give me some pointers.

Problem #1 is the sprocket carrier does not fit the wheels because boss for the wheel bearing on the wheel is too big a diameter and too long, to fit inside the carrier, all the cush drive etc, appears the same and fits.

Other issues include the rear brake, I don't have a suitable rotor for the stock caliper, cannot find that diameter, so was intending to use a modified GPZ550 rear caliper which fits the rotor I have for my wheel. However it seems here that the spacers etc. must be different with the police wheel on the caliper side for it too fit.

It now looks like I have two choices, either ditch the police wheel and go with a KZ650c rear wheel or buy a lot more stuff for my Police rear wheel which still may not fit unless I can work out exactly what is needed to complete the install. I wanted the Police rim also for the extra width, now I'm feeling like I care less about .35", given the other issues I'm encountering.

Police rear wheel has never been a direct swap
The 18" wheel from a 78-80 z1r or mk2 are

And good luck finding those...although I think that's typically the 18" front that people are after.

Just about any 18" from a Kz900 or Kz1000 (excluding police) should fit, I believe.

kzrider.com/forum/5-chassis/544451-18-rear-wheel-on-ltd-1000

And if it's really an A2 it should have come with an 18" rear from the factory, I believe.

DoubleDub wrote: And if it's really an A2 it should have come with an 18" rear from the factory, I believe.

Unfortunately someone put Lester Mags on it, but went with a 16" rear. I did find out to day why a LTD uses a different brake caliper, because if you have a 16" rear wheel with an A2 caliper it's too big to be able to remove it from the rotor unless you unbolt the rotor as well. there isn't enough clearance between the rim and rotor. PIA. I'm glad I found that out before getting a flat one day

It's definitely an A2, from frame and engine number and even has the information stickers for an 18" rear.

spdygon wrote: Police rear wheel has never been a direct swap
The 18" wheel from a 78-80 z1r or mk2 are

I wish I could find the article I read where it said it was straightforward - it's definitely not that simple, but I believe it can be done if I get the correct sprocket carrier and axle spacers. Having got this far I think I will persevere a little further with it having polished the rim and had the tire mounted. I managed to find the correct year Police axle with the spacers on eBay and I can get the sprocket carrier to suit the wheel. My caliper looks to be exactly like the Police caliper where it fits the axle. Now it will depend if the overall width of the Police swing arm is the same, if not further mods will be required.

Currently I'm stuck with the sprocket carrier not fitting on the one side and not having a spacer the right size to go inside the seal on the brake side. If I have both of those I can either make spacers shorter or shim them out to suit the overall axle spacing.

I finally got my Police Rim on the bike, so I thought I'd document what I did finally, so it may assist someone else following the same route. Some of this may not apply to someone who already has a Kawasaki rear alloy rim, some of the problems I encountered may be because my bike was fitted with Lester Mags that were perhaps designed to fit all the other parts from the original wire rims. Someone going from wires to Kawasaki Mags would likely encounter the same problems I did.

I started out acquiring a 1988 18" Police rim. The first and obvious problem was the rear brake. Try as I might I could not find a rotor with the 7 bolt mount, that was the 295mm diameter of the stock rear brake. I had two front rotors from a GPz750 knocking around which would bolt to the rim. but were 260mm in diameter. I then began to search for a rear caliper that would work with a 260mm rotor and found that a GPz 550 used that size, so I thought I'd locate said caliper - more about that later.

Looking at fitting everything on the axle, initially looked straight forward, until the day I tried to put it all together. The Police rim and the stock sprocket carrier turned out to be incompatible, the boss on the wheel where the bearing sits is longer so the recess in the sprocket carrier is too shallow. Secondly the cush drive from the wire wheel doesn't fit properly, it's identical in every respect other than it doesn't have the little semicircular cut outs molded into it that fit around the same shape in the hub casting. There are also issues with the stock spacer on the brake side, the existing one is too big in diameter to go inside the bearing seal on that side. The stock spacer on the chain drive side is however the right diameter for the seal and the correct width for the wheel to be centered with the Police bike Sprocket carrier etc. Coming to the brake side it's then a matter of getting everything into the available space. With the stock Police spacer against the wheel bearing and the chain tensioner in place there is only about 20.5mm of space available for the caliper mount. A stock Police caliper mount is about 23.9 mm thick, if you plan to use the Police rotor and caliper. My GPz 550 was about 25.7 mm thick, I ended up getting this machined down by 5mm to give a perfect fit, but I also had to enlarge the bore of the mount to 20mm to fit the axle. I also had to enlarge the torque arm attachment point hole to 12mm to match the existing torque arm, with which it lined up perfectly when set up. The 5mm is removed from the outside of the caliper mount boss, if you see the original caliper mount, that will be obvious,

I've attached pictures, but to recap if buying a Police Wheel, get the whole set up, axle spindle, spacers and sprocket carrier, that way you will have all you need. Starting at the chain side of the swinging arm you will have the tension adjuster, then the stock round spacer which works with the Police sprocket carrier to center the wheel with regards to that side, there's a spacer in the sprocket carrier, I used the Police one here, although I think this is the same as the stock one. Then you have the wheel assembly and on the other side use the Police spacer that goes between the wheel bearing and the caliper mount, the stock one is too big in diameter to fit inside the seal. You then just have to modify the caliper to fit between there and the chain adjuster on the far side.

Here's the GPz550 caliper in place, I like the fact it's a lot more compact than the KZ1000a rear caliper, I also like the smaller diameter rotor combined with the 18" wheel giving a more open look.










I hope this will help someone else pursuing a similar modification, overall I like the Police rim, I could have done an easier conversion with a KZ650c rim that would have accepted my stock rotor and caliper, but I like the extra width of the 2,5" rim, i think that's a better width for a 120/90/18 tire and as already stated I find the 260mm rotor and the smaller GPz 550 caliper visually more attractive. It must also save some weight too. For my taste, the 18" wheel just looks so much nicer than the 16" it came with and while not stock it returns the bike to the look of the KZ1000A2 it was built as, rather than the LTD look the Lester mags with 16" rear had given it.

The finished article on my ride today.

spdygon wrote: Police rear wheel has never been a direct swap
The 18" wheel from a 78-80 z1r or mk2 are

Do you know if any of the wheels you list are tubeless? Looking for tubeless for my '80 z750 ( 750cc jdm mk2)?

I forgot to mention in my excitement at getting the wheel on and the snags hit along the way, that part of my original reasoning for using the Police Rim was that it was a tubeless rim. The extra width and it being tubeless were the original drivers for going down that particular road.

If you want a tubeless rim then I think your options are the 80's and up Police rim or the 81 and up rims used on various Kawasaki models GPz, Kz1000J, KZ1100 etc. Given they have the 7 lug rotor that attaches to the rim, I think they are likely the same as the Police rim, but even if not exactly the same they would provide the same sort of conversion challenges. My understanding is any pre 81 Kawasaki rims are not tubeless rims. although I once read the Z1R might have got a tubeless rim a little earlier.

The rims on my '79 KZ1000ST (KZ1000E1) are tubeless. Whether they're original or not I'm not sure. That would suggest the mkII would be tubeless too.

I have a rim from a 1980 KZ1000 LTD and that isn't marked as tubeless, no idea why the ST would have tubeless rims as the front seems to be the same as other KZ's, albeit the rear is different because of the shaft. ST rims I've seen are 19x1.85 wide instead of 2.15 though, so perhaps they were different despite having the 4 bolt rotor. I'd still like to get a tubeless front at some stage.