KZ900 Top Idler Wear Help

Attempting to reinstall my camshafts after replacing a couple valve shims, which is a real pain in the ass by itself. I noticed the top idler seems to have a lot of slop in it, although the gear still spins quite easily by hand. I assume, just like any bearing, that there should be no wiggle in it whatsoever, aside from a little side to side walk on the shaft it's mounted on. However, I can find no information anywhere to confirm this, and I would like to know for sure before shelling out a hundred plus dollars for a new one. Can anyone help?

How many miles on the bike. If it's that bad the rest are too and must be replaced. I use Liska rollers.
Steve

Hi coyoteduster4406,
We see the rubber "donut" insert between the roller bearing and the chain tooth ring fail far more often than the roller bearing itself. A small amount of wiggle between the bearing and shaft is inevitable with roller bearings, more so than plain bushings.
See if you can press the rolling element out from within its rubber surround just by using your thumbs. If so, time for replacement. As SWEST says, it might be time to replace all the camchain tensioning components.

Good Ridin'
slmjim & Z1BEBE

Our newest vendor here on KZRider is Liska Racing .
There ad appears at the lower right of each page just below the last post..
So how is that for having a expert available.
Send them a email for parts or questions you may have
Dave

I thought the Kz900 shims were on top. Why "reinstall camshafts"? Is it easier to just remove the cams anyway? Or did you convert to a shim-under-bucket system?

Hey guys
The bike has around 40,000 miles on it. I've owned it for almost a year and have had all of 3 days of seat time on it due to cleaning up after the POS P.O. I pulled the cams because the intake cam was off by one pin, and in the paperthin hope that I might be able to swap some shims around to get them in spec (big surprise, that wasn't an option).
I'm not sure what you mean by pushing the bearing out with my thumbs. There's barely any room in the top idler to get a screwdriver in there, let alone my fingers. The rubber does not appear worn to my eyes, it has marks where the outer links would press into it but no chunks missing or anything like that. I will see if I can successfully upload a video of what I'm seeing. I've spent so much goddamn money on this thing already, I just wanted to be able to ride out the summer before I took it off road again to put the correct LTD tank and front fender back on it.

Thanks for all the feedback by the way

Unfortunately I cannot upload a video from my phone so I guess that's not an option

This is what can happen if the rollers go too long. The front guide is gone.
Steve



kzrider.com/forum/2-engine/597654-poser?start=80#690209

coyoteduster4406 wrote: ...
I'm not sure what you mean by pushing the bearing out with my thumbs. There's barely any room in the top idler to get a screwdriver in there, let alone my fingers....

Hi coyoteduster4406,
Apologies, that was the wrong response. Had the lower idlers in mind for some reason. Brain fart...:blush:

A new top idler looks like it has about .020". wiggle, not to be confused with side-to-side end play along the shaft. We didn't mike it, but that's pretty close. Looser than that or exhibiting any noticeable radial play calls fro replacement. That type of slop is usually from the rubber "donut" deteriorating that's between the outside of the outer bearing race and the inside if the outer ring gear that has the chain teeth around it. In that respect it's constructed the same as the lower idlers.

Good Ridin'
slmjim & Z1BEBE

In 78 I pushed my luck and broke a cam chain. Bent valves, the works. I then went with a 1015 kit. It was the same price or cheaper then new pistons and rings. Besides I got more power out of it. That's why I'm so serious about the rollers.
Steve

Alright, well you've all convinced me that I need to replace the idler gears top and sides. Which means pulling the head. How about the tensioner and guide roller? Do they mean pulling the jugs?