intermittent cam chain noise

Hi all, I'm getting periodic noise from my cam chain - sometimes it's on, but then sometimes it's off, and the engine purrs beautifully. Anyone have an idea of why it might be intermittent? This is on a 1980 kz650. I have adjusted to semi-auto-tensioner, heard the spring snap out, re-tightened, but the noise is still there, and still intermittent, being off for minutes at a time, and on for minutes at a time. Certainly more often on than off though.

I have replacements for the 2 springs inside the tensioner - should I replace those or just get a new one, or is this something else? When I was doing my shims, the cam chain guide on top looked to be in OK condition, but I didn't inspect it very closely, and I don't know what's going on below.

The cam chain rollers and idlers in these engines can deteriorate and cause problems like this. If it were my bike I would bite the bullet and disassemble the top end to replace the worn and deteriorated parts. You may want to look for black rubber chunks from the rollers and idlers in the oil pan. Good luck!

I would check the tensioner first before stripping it. The 'auto' tensioners aren't too clever on these, a rebuild with new springs -or shimmed with some washers and cleaning up the cross wedges with wet and dry might be a fix. a manual tensioner is another option.

The gpz550's had revised tensioner springs, not sure about the others.

Camchains have a 'bunch of keys' jangle sound about 3 or 4 k rpm, but usually constant and becoming audible at this rpm range.

I found that two of the cam chain guide rollers in KZombie were worn heavily but I wasn't able to determine this until they were entirely removed from the bike. The cam chain keeping them under tension would mask the issue - worn out roller bearings at their centers. I don't know what this would have sounded like since I've never had KZombie running yet but I can't imagine these would have sounded very good - like when wheel bearings begin to go the way of the Dodo - "Did you hear that? WTF was that noise?" :dry:
but once you get them in your hand and feel all the play between the races you're amazed that the things were working at all without going Chernobyl on you.

There is some document somewhere about tension spring length. I forget if that's a 550 or 650 problem or not but it is easy to check and just need to measure the spring's length. Sorry for the vagueness. I read it in a manual I think. Maybe it was a Kawasaki manual even? :laugh:

Yep. My tensioner springs were under spec, and I had purchased some new ones a while ago, so I rebuilt the tensioner (at least in replacing the 2 springs). but that has done nothing for the noise, well it has possibly made it more consistent. . I will try machining a manual tensioner in the next week or so and see if that does it, as I've seen people complain about the automatic ones in general, and if that doesn't work, I'll open up the top and take a look at those cam chain rollers and idler.

wrenchmonkey wrote: I found that two of the cam chain guide rollers in KZombie were worn heavily but I wasn't able to determine this until they were entirely removed from the bike. The cam chain keeping them under tension would mask the issue - worn out roller bearings at their centers. I don't know what this would have sounded like since I've never had KZombie running yet but I can't imagine these would have sounded very good - like when wheel bearings begin to go the way of the Dodo - "Did you hear that? WTF was that noise?" :dry:
but once you get them in your hand and feel all the play between the races you're amazed that the things were working at all without going Chernobyl on you.

There is some document somewhere about tension spring length. I forget if that's a 550 or 650 problem or not but it is easy to check and just need to measure the spring's length. Sorry for the vagueness. I read it in a manual I think. Maybe it was a Kawasaki manual even? :laugh: