Cam Chain & Top Idler Query

[Tonto]

Chaps, apologies my spannering skills are a bit limited and any advice would be appreciated.
Was checking valve clearances today on my Z1000A1 project - bike is still on my ramp but starts and runs fine with no noises or rattles etc (meant to be low miles but no guarantees).
A couple of inlet clearances were tight, but more worryingly whilst rotating the crank I noticed that the cam chain was not at a constant tension and appeared to have a slack spot. I dismantled and checked the tensioner which appeared to be functionng Ok. I then whipped off the top idler gear, the gear was hardly worn but felt loose on its shaft (as if its needle rollers were failing).
I was going to replace the cam chain and top idler, or get he bike looked at by someone who knows what they are doing - but before doing either is there something I am missing and should be checking out ?

The bike's been running strongly for a few workshop sessions without any drama, so reasonably I did not think there were major problems: maybe I am being delusional.

Cheers Tim

[chrisu]

you did have the bike at TDC before you removed anything didn't you ?

[zed1015]

It is very unlikely that the needle bearing has failed but the rubber that is sandwiched between the outer sprocket ring and the inner bearing holder degrades over time and becomes detached .
This is what may have happened to yours .
It is a common occurance and best replaced with a solid Liska type.

[Tonto]

Thanks, will acquire / fit a new one.
Chrisu - yes crank was at TDC, but since then I think my ineptitude may have caused me a new issue :-(

[Pigford]

Thanks, will acquire / fit a new one.
Chrisu - yes crank was at TDC, but since then I think my ineptitude may have caused me a new issue :-(

You ain't bent some valves now, have you?

Been there and done that whilst adjusting auto-tensioner....... not once, but twice in the last 30yrs