GPZ750 Cam chain adjuster

[Eastoe]

Finally got around to checking valve clearances on my 82 GPZ750 and am concerned about the automatic cam chain adjuster.
When I turn the engine over the cam chain goes slack momentarily just before TDC, then picks up again.
If the cam chain tensioner is working propoerly then I figure the cam chain should be a smooth roll all the way round.
As I've mentioned before the bike hasn't been used for 20 years and perhaps the tensioner is now sticking, needing disassembly and greasing. does this sound correct?
When I had the engine running it was quiet as a mouse with no cam chain noise.

[h.b.bear]

If its running quiet as a mouse don't touch it as it is doing its job !! A lot of folk have chucked away the auto one over time and installed a manual one. As you may know you will usually get a rattly engine on start up but that's a Kawasaki thing with the older models

[Gosling1]

......When I had the engine running it was quiet as a mouse with no cam chain noise......

as per HBBear's advice - if you get no noise when the motor is running, I would leave the CCT alone. These auto tensioners do eventually bite the dust but you will hear this as it gets worse - if you can't hear anything at the moment - its still good.

A manual CCT is always a better improvement though - set & forget. You can modify the auto tensioners to a manual style if you want to, but the APE tensioners look a lot tidier

[Eastoe]

Well, that reduces my work load.
It's virtually ready for rego but sometimes it's hard to work out where to stop.

[Gosling1]

got any pics ?

[Eastoe]

of the bike or the cam chain issue?

[Eastoe]

Cam chain tensioner fixed.
Installed cams after adjusting clearances and as the manual mentioned I had to replace the bolt that stops the tensioner pushrod from falling into the engine with a longer bolt to lock it into position.
So when I read the instalation procedure the manual mentioned that the original bolt should have a washer under it.
So I pulled it out again and no washer. so someone has removed it and replaced it without the washer and I think this has been enough to stop the tensioner pushrod from moving freely and hence the chain going slack at TDC.
I put it back in with a copper washer and it turns over beautifull now with even tension on the camchain all the way round.
What a difference a washer makes. these are the little things I like about a genuine manual. very happy.

Two of the valve clearances were on zero so after reducing the shim size by .15 they are still too small but at least they have a clearance now.
Kawasaki are nil stock of 2.25 shims and the workshop I got some shims from yesterday don't have that size.
i'll try a few other places today but has anyone here got a 13mm x 2.25mm shim?

[Gosling1]

......of the bike or the cam chain issue?.....

of the bike - I've seen heaps of cam-chain issues

Good to hear that the auto CCT is now doing its job. These are not known as the best CCT's in the business but when they are working OK then best to leave them be.

I probably have a 2.25 in the box in the shed but its about minus 45deg out there at the moment........ will check it out over the weekend and let you know. Once the shim sizes start hitting the 2.10-2.15 mark, its time to start thinking about new valve seats.

[Eastoe]

I spent 20 minutes with a 2.30 on an oil stone last night and got it down to 2.25 so no need to brave the freezing temps now. thanks anyway. all clearance are 0.13 - 0.15 now and as I said the cam chain is running smooth so i'm pretty happy now.
One shim is down to 2.10 so i'm a bit worried about that but I guess I'll see how it goes.
2 valves measured 0 when I originally checked them and only came up to 0.05 after reducing the shim size by 0.15 so those valves must have been staying open for a while in it's last life which i guess would damage the valve seat.
Perhaps that might be why it was parked up 20 years ago.

[Gosling1]

yes that sounds right mate - once the clearances close right up, these motors get really hard to start from cold - OK to start when warm though. I can imagine that 20 years ago, someone would have just got the shits with a motor that didn't want to start at all so decided to park it up.......

[Eastoe]

Just when you think everything is ok...........
When I put the cam cover back on the cover is pivoting off the centre.
The cam chain guide is hitting the cam chain by quite a bit causing the cover to rock.
It was an old gasket which was fairly compressed but now i've taken it off again and cleaned it up there is about 4 or 5mm difference and I don't think the new gasket will take that much up so the cam chain will run along the guide to the point that it will chew it out and spread through the engine. As if it will need 2 gaskets to clear.
Doesn't make sense. anyone seen this before?

[MickLC]

Are you running the cam chain under the center roller or on the top? It's meant to run underneath.

[Eastoe]

This model doesn't have the centre roller of the Z650.
Cam chain is heavier too. I think they called these a hyvo chain or something.

[MickLC]

Yeah but there's a guide there and the diagram I'm looking at shows it above the chain still.
I haven't seen the top end of one in person though so can't say for sure.

[Eastoe]

Guide inside cam cover is interfering with the cam chain.
Cam cover is straight. Guide looks in good condition.