rattling sound

my kz900 "rattles/pings" any time i roll the throttle. if i gradually speed up, its o.k. if i roll on it hard it rattles/pings, then once i level out at a good speed it goes away. is this a timing issue? like spark advance or something?

sounds like a timing thing, have you looked at the advance mech ??

no, not yet. what would be the best thing to lubricate it with if i find it sticky?

arobsum wrote:

no, not yet. what would be the best thing to lubricate it with if i find it sticky?

Completely disassemble it and use any multi-purpose moly grease to lube the shaft and weight pivot points. Be sure the springs are in good condition. Make sure it snaps back positively when you open and release it with your fingers. That's about it.

To add just a bit to savedrider's fine post... the springs are compression type. DO NOT try and pull them OUT when you remove them as they will just stretch and you will ruin them. If you remove them, take care not to overly stretch them.

Have you tried the simple things like trying some higher octane gas? It's entirely possible that your compression ratio is up because of carbon deposits. If so gas that worked fine last season might ping this year.

Another thing is elevation. Here in Bend, Oregon I can run regular in all my bikes but if I'm going to Portland, a drop of nearly 3000 feet, I'll definetly need high test fuel to avoid detonation. Have you always run this bike at the current elevation?

In order for your advance mechanism to be at fault, it would have to be seized in the spun out position. Check it out. Are the weights out or in? If they're in while at rest, they're not the problem.

KZCSI