Loud Rattling Coming from gearbox

Hey Guys,

I've been stuffing around with my 82 z1100 a2 (shaft drive) for a while and i've just started riding on the road again. I've noticed a pretty bad rattling sound coming from the bottom of the engine/gearbox that only occurs at idle. I have little to no experience with shaft drives so i'm not sure at all what's going on in there.

Just wondering if anyone had any ideas what it is before i start tearing it down?

Cheers,

PS i'm new and am trying to add a signiture but it's not letting me save edits on my profile

What rpm is your idle set at? Ed

It actually goes up and down a fair bit but usually just under 1000

Cheers,
chris

'82 Z1100 A2

Before disassembling anything, would first perform a complete tune-up, including carb sync, then set the idle rpm at 1200.

Is there combustion on all four cylinders?
Can spray water mist onto exhaust headers shortly after starting cold engine to determine which cylinders are combusting (water vaporizes and sizzles off) and which aren't (water runs down the exhaust pipe).

Good Fortune!

Patton wrote: Before disassembling anything, would first perform a complete tune-up, including carb sync, then set the idle rpm at 1200.

Is there combustion on all four cylinders?
Can spray water mist onto exhaust headers shortly after starting cold engine to determine which cylinders are combusting (water vaporizes and sizzles off) and which aren't (water runs down the exhaust pipe).

Good Fortune!

+1, carby tune to start with (after checking compressions)

Unsynched carbs will cause a rattle at idle and what Patton said set idle to 1200 rpm.

Last time i checked all cylinders were firing. I normailly just spit on them but i guess a water gun is more civilised

Cheers for the advice, i'll get the carbs synced and set idle and i'll let you guys know how it went.

Thanks!!

'82 Z 1100 A2

A couple years ago the three starter-clutch mounting bolts became loose on my engine. Whether that caused magnet breakage on the engine rotor (or the opposite), I don't know. But that is what happened in my case.

Before discovering the culprit, I thought sure something was loose behind the transmission cover.

Somehow my attention arrived at the generator cover. When lightly placing my hand on the cover, I literally felt something wasn't right behind it, with engine idling and the bike on the center-stand. If you try this, do it while the motor is warming up, because that cover becomes very-hot.

This may not be the problem you are having, but it could be.

See: www.kzrider.com/forum/2-engine/540846-oh-brother#540846http://

Good luck...

Thanks Daveo! felt a bit of a rattle through the alternator cover. Took it off and one of the magnets has cracked. Not sure how though... Would the broken magnet be all that is rattling? It seems pretty small to be making so much noise.

Make sure it's not just your exhaust pipe clamp rattling before you decide to gut it

Chris, while it may not be the only thing causing the rattle, you need to replace it and retest. With these old bikes, it is entirely possible that you have multiple causes which are combining in one overall issue.
I also suggest that you check your valve clearances prior to the carb synch, as this will affect the synch process.

Chris_Z1100 wrote: Thanks Daveo! felt a bit of a rattle through the alternator cover. Took it off and one of the magnets has cracked. Not sure how though... Would the broken magnet be all that is rattling? It seems pretty small to be making so much noise.

See: www.kzrider.com/forum/2-engine/540846-oh-brother#540846http://
If the magnet piece is loose, it is possible. Post a close-up picture of the broken magnet if you can.
This is likely where the magnet fragments have gone. Pic taken 9/05/10