Noise on GN when slowing down

[MaxCannon]

Recently I've noticed a noise on the GN when off the throttle , i.e slowing down and still in gear.
It's a sort of chattering noise that goes away as soon as I pull in the clutch
It doesn't occur when on the throttle, either full, half or hardly any.

I thought it was brakes at first but it occurs when hard on the brakes or not on them at all.
I check the chain fairly often and it isn't dry and I check the engine oil level weekly and it's still on the full mark.

What should I be looking for / worried about ?

[sunhuntin]

i would have said oil, but youve already disproven that, so im stumped.

[Sully60]

Recently I've noticed a noise on the GN when off the throttle , i.e slowing down and still in gear.
It's a sort of chattering noise that goes away as soon as I pull in the clutch
It doesn't occur when on the throttle, either full, half or hardly any.

I thought it was brakes at first but it occurs when hard on the brakes or not on them at all.
I check the chain fairly often and it isn't dry and I check the engine oil level weekly and it's still on the full mark.

What should I be looking for / worried about ?

What happens when the bike is idling with the clutch lever out (clutch engaged)? Does the rattle happen here too or does it only happen when the bike is in motion?
As the policeman would say:
Just trying to eliminate you from our investigation

[MaxCannon]

No noise at idle, it only happens when off the throttle, in gear, with the clutch out (i.e hand off the lever)
Pull in the clutch and noise disappears

[Spuds1234]

Check your chain tension.

My bike does this when I get lazy and my chain gets sloppy as hell because I havnt tensioned it in a month.

[xwhatsit]

You sure it's not the exhaust?

I get a bit of `twitter', especially from high engine speeds, when I close the throttle. It's a single *shrug*. I think exhaust crackle quite prolific amongst GN250s; nothing to worry about if that's what it is.

[Max Preload]

Sounds like a chipped gear tooth.

[Pancakes]

Thats what I was gonna say.

Open it up and clean it out. The return on the GN's is small so some stuff stays in the side chambers. The right side is the gears, that left side cover needs the right thickness gasket tho, if it's too thin the reduction gear for the starter will rub on the casings and it won't start. Can uses a sheet of gasket paper and some washers at a push.

And if you do take the left cover off three springs and rollers may pop out, keep them and if you didn't see where they came from PM me or get someone to come over.