cam chain rollers worn, how to find?

I am currently doing a top end rebuild on a '77 KZ650B1. The clock reads 30K and inspection and measurements look to be at approximate tollerances for this mileage if the bike were maintained fairly well. The only parts I am finding difficult to replace are the two hard rubber cam chian idler rollers, one is pushed by the tensioner, the other sits between the crankcase and the bottm of the cylinder block in the center all alone with no attached steel shoulder like the other one. The age and use are starting to chip away at these two rubber wheels/rollers. Bone yard less used ones are still 30 years old. Where can I find new ones, or maybe I could replace them with idler sprockets? Sprockets look more durable. Also, the single roller down low has an asymetric quality to it, right? I am asking for confirmation on weather it has a ridge on one side that sticks up a bit outside of the chain travel. There is a ridge in the center, too, that the chain rides on. Does the ridge face the left side of the bike or the right or does it matter. I seem to have missed observing this feature when disassembling.

From older posts, the roller that gets pushed in by the tensioner is no longer avaiable. The roller used in the 900 bikes fits but is something like 4mm smaller (i can't recall for sure). SOme folks have switched that rubber wheel out for another of the idler gears...i dont know how that works for them (seems as it would bind when the adjuster is very far in).

THe other rubber wheel i have heard little about, some guess it would be the same as the z1/900 wheel even thought part numbers dont match, but no one has confirmed this...

I am thinking of having both machined from blocks of synthetic rubber... but i dont know how that will work for me till i talk to some of my buddies about it.

thanks, I did do a cross check on the Kawasaki web site under owner info and parts diagrams and the OEM numbers are different. I haven't heard "I did this in my engine and it worked great" from anyone. Jeff at Z1 did not have any quick answers but did touch on replacing with sprockets, alot of race engines have this done. I have heard there is a Japanese after market company that is puting out exact replicas on all parts for some of the older bikes, but not so sure about my model. Worst case scenario, I'll put 'em back in. I just hate weak links, though.

well if you happen to find a solution please let me know, because when i get back to the states this will be high on my list.

It really seems to me that the tensioner would cause the chain to bind between 2 sprockets... race motors have the advantage of ultra low miles, i would like to have another 25,000 worry free miles on this top end without having to tear into it...

You are in luck. I just went through this exercise.

In the late fall, I had some concerns with my cam chain slipping so I took off the head and discovered the cam chain roller (on the cam chain adjuster assembly) was offering a little more sideways play than I was happy with.

Luckily my friend had his '77 Kz1000 LTD apart for a rebuild, compared the two parts and they were identical. I simply swapped in my buddies 1000 sprocket and it worked fine. Of course I bought him a new one and it set me back over one hundred bucks.

Kawasaki Canada was back ordered on the 650's gear but they had the 900/1000 in stock. The part numbers are different but the parts are interchangeable between the 650 and the 900/1000.

Cheers-Colin Firth-Ontario Canada

Now i know i remember a post where Jeff Saunders said the 1000/900 rubber roller (the one pushed by the tensioner) was close, but something like 5mm smaller.



:blink: :dry: :blink:


here is Jeff's thread, i was wrong the 650 is 5mm smaller...
kzrider.com/component/option,com_joomlab...id,2/id,43832#43832/

Post edited by: hardr0ck68, at: 2007/02/15 04:13

So you are using the kz1000 rubber roller with no issues?

Post edited by: hardr0ck68, at: 2007/02/15 04:30

30,000 miles none of these should be bad. Even 30 yrs old although definately a factor, it's more the amount of heat and use more than age. Of course more miles mean more heat and wear. If yours are really bad which I am surprised at, the stuff at a junkyard would work just fine. I've always been a kind of "if it isn't broken, don't fix it" kind of guy and my sprockets went over 135,000 miles before the rubber deteriorated, and that rear idler roller went the whole 162,000 miles before I retired my 1978 KZ650B original engine.

I'm appreciating all the comments. I embrace the saying, "if it ain't broke, don't fix it." I still have not heard anyone's confirmation on the asymetrical feature to the lower idler roller. It has this edge on one side that sticks up. That is the part of the roller that is looking questionable, and which side of the bike does the high ridge go towards, left or right? Maybe if this ridge isn't all that important I could sand it down a bit since it's sharp and chipped a bit. Thanks, Ron. You're not too far from me. Just bought another project 1977 KZ650 today.

hardr0ck68 wrote:

...here is Jeff's thread, i was wrong the 650 is 5mm smaller...
kzrider.com/component/option,com_joomlab...id,2/id,43832#43832/

No, the 650 rear guide is the larger one - you can fit a cam chain sprocket in the 650 guide bracket, but you can´t in the 900/1000 bracket.

Btw, as Reborn says, the 650s and 900/1000s that use single roller cam chains use the same cam chain sprockets even if the OEM numbers are different.

Some more info in this thread.


Oops, sorry, missed your last question: no, the lower cam chain guide (the one that sits at the cylinder base) should not look asymmetrical, it should look like the one pictured below, a NOS OEM roller I was lucky enough to come across, the only ridge should be in the center.



Post edited by: OnkelB, at: 2007/02/15 12:26

Well, mine does not look like yours. It definately does not have an even shape.

I'm trying to figure out how to post pictures. Let's see if my cam roller comes up.

I'm stumbling through trying to get my images to the correct size for the post, not sure easiest way. hopefully you can see my picture this time. Any tips on picture posting anyone?