Weird noise

[keithbuckby]

yeah I know I should be taking my bike to a mechanic, but just bought a house so scratching at the moment, when I throttle off there is a rattle coming from engine, sounds like a chain rattling sort of, if I pull the clutch in it stops. no noise at all when revving in neutral just seems to be when in gear and tension off chain maybe. thanks in advance for any clues

[MSTRS:Me]

Cam chain most likely. Replace it and/or tensioner.
Otherwise, does your bike have a primary chain? The drive from the crank to the clutch.

[keithbuckby]

although someone told me the cam chain does it at idle as well. no primary chain.

[MSTRS:Me]

A cam chain tensioner is usually acting on slack side of the chain. The opposite reach to the 'drive' side. So on deceleration the drive side goes slack, causing the rattle.
Chain and tensioner need to be replaced. Ignore the signs at your (engines) peril...

[CookMySock]

I do not think the camchain goes slack on overrun. I reckon thats bogus.

Some clutches do chatter when they are engaged, and go quiet when the lever is pulled in. Yours sounds more like some gearbox related thing. How long since the oil was changed ? Is it only at a small range of revvs, or all revvs?

Steve

[AllanB]

Is this on your 1982 GPZ1100?
How many kms on the beast?

It's 27 years old - if original and the kms are up there then I'd agree that is the cam chain and tensioner. Obviously a new noise so get it looked at pronto.

Does that bike have a auto tensioner or manual - my 82 750 Kawa had a manual one. If manual, when was it last adjusted - have you adjusted it at all?

[elevenhundred]

I do not think the camchain goes slack on overrun. I reckon thats bogus.

Some clutches do chatter when they are engaged, and go quiet when the lever is pulled in. Yours sounds more like some gearbox related thing. How long since the oil was changed ? Is it only at a small range of revvs, or all revvs?

Steve

Cam chains can go slack on overrun if the tensioner isn't doing its job, it can cause the cams to go momentarily out of time allowing them to contact the pistons.

[keithbuckby]

I did the oil change in december, I guess at this age of bike things are starting to play up, the tensioner is automatic, but I will have a look at it this weekend and make sure it is all ok.

[vifferman]

when I throttle off there is a rattle coming from engine, sounds like a chain rattling sort of, if I pull the clutch in it stops.

Are you guys sure this a camchain rattle? You all seem to have overlooked this bit.
Lots of bikes have rattly clutch baskets and/or gearboxes - mine does, and it doesn't have a camchain.

[vifferman]

Cam chains can go slack on overrun if the tensioner isn't doing its job, it can cause the cams to go momentarily out of time allowing them to contact the pistons.

Not quite right; it's usually more that the camchain gets a bit of slack in it, then as the slack bit gets fed onto the cam it loops up and can skip teeth on the cam.

[hmmmnz]

i'd be checking the cam chain as well,
who gives a fuck about the clutch rattle, i'd rather check it and be sure,
and they will rattle on overrun when there is load on the bike,
pull the tensionor out and have a look at the crappy little spring inside it,
quite often they fail,
if its ok, then a longer bolt in the end of the tensionor might help preload it a bit more,
have fun

[rok-the-boat]

Could also be a slack and rattling rear drive chain. Safe to check. My DR has rollers that guide the rear chain - one siezed up slightly and it immediately started vibrating as the chain slid over it rather than rolling on it. Took it to bits, greased it up, and now it's fine. OK, I know yours probably doesn't have these rollers but drive chains can make noise.