GN250 clunking noise?

[magicmonkey]

Recently I've been hearing a clunking noise from the bike, mainly when on neutral throttle or changing gears. It sounds like it's coming from near my left foot so I've checked the chain and that's at the correct tension (can't pull it off the rear sprocket at all and the flex is about 1 inch) so I'm starting to worry about the gear box or clutch, if anyone has any ideas on where I should start looking I'd really appreciate it!

[huff3r]

My GN clunks quite noticably when changing gears too, thought it was normal... although my lever is bent and needs adjusting lol

[Geemsee]

Presumably you mean when you're moving along? If so you could try coasting along (downhill on a quiet road obv!) in neutral with the engine off, this would at least tell you if its something to do with the chain and sprockets, sometimes if the chain isn't kept lubed it'll develop dry or stiff links, meaning the chain doesn't track freely over the sprockets or if its really worn the teeth on the sprockets can get hooked and catch on the chain, but this is normally on more powerful bikes.
Alternatively you might have a loose front sprocket, so whip the cover off and see if the lock nut is good and tight, at the same time check to see if theres any play in the driveshaft, a little bit of in and out is ok but side to side would be bad
If that doesn't at least find the problem you might have to start looking elsewhere!! best of luck!!

[Cheshire Cat]

See theeeeeeeeres your problem.....Its a GN!!!

[huff3r]

See theeeeeeeeres your problem.....Its a GN!!!

Hey, nothing wrong with a GN... there a perfectly good bike... sometimes... oh come on, just believe me already.... i have no proof

At least itsa bike and it goes and stuff

[YellowDog]

Errrr, if it's my turn, my guess is:

A loose spring on the centre stand causing the clunk.

Good advice trying to make it clunk in neutral so that you can be sure that it's not the gearbox.

Good luck.

[magicmonkey]

Presumably you mean when you're moving along? If so you could try coasting along (downhill on a quiet road obv!) in neutral with the engine off, this would at least tell you if its something to do with the chain and sprockets, sometimes if the chain isn't kept lubed it'll develop dry or stiff links, meaning the chain doesn't track freely over the sprockets or if its really worn the teeth on the sprockets can get hooked and catch on the chain, but this is normally on more powerful bikes.
Alternatively you might have a loose front sprocket, so whip the cover off and see if the lock nut is good and tight, at the same time check to see if theres any play in the driveshaft, a little bit of in and out is ok but side to side would be bad
If that doesn't at least find the problem you might have to start looking elsewhere!! best of luck!!

I cleaned the chain this weekend, part of that involved removing the front sprocket cover and cleaning 5 seagulls worth for crap out of it and giving the sprocket itself a quick clean, I'm pretty sure there was no play in it but I'll double check again tonight (tools are at home, i'm at work) The chain didn't have any dry or stiff links in it and the sprockets themselves are in pretty good nick so I can be fairly certain in saying they aren't at fault (although I'll have a double check tonight as well, just to be sure!). As for the sprocket nut, I'm sure that's on ok as the bent up washer hasn't moved around it at all.

[Cheshire Cat]

Hey, nothing wrong with a GN... there a perfectly good bike... sometimes... oh come on, just believe me already.... i have no proof

At least itsa bike and it goes and stuff

hardly! it clangs and clunks.....like he said.

[magicmonkey]

hardly! it clangs and clunks.....like he said.

Still, at least it's a step up from a [strikethrough]puff-mobile[/strikethrough] scooter!

[Cheshire Cat]

Still, at least it's a step up from a [strikethrough]puff-mobile[/strikethrough] scooter!

Yes, but a Vespa is much cooler than a GN.

[magicmonkey]

Yes, but a Vespa is much cooler than a GN.

only in the same way that pink is cooler than black. ie. for girls

[UberRhys]

Yes, but a Vespa is much cooler than a GN.

This is true IMHO. My GT200 goes faster, carries more and is a heap more comfortable on long hauls from Auckland to Rotorua/Taupo than a GN will ever be. Still there is a special place for GN's and SR's. Didn't everyone learn to ride on one of these beasties?

But at the end of the day 2 wheels is freedom so really, ...

[huff3r]

Yes, but a Vespa is much cooler than a GN.

Yeah, but im much cooler than a GN too, and you dont see people riding me in their dozens

[magicmonkey]

Presumably you mean when you're moving along? If so you could try coasting along (downhill on a quiet road obv!) in neutral with the engine off, this would at least tell you if its something to do with the chain and sprockets, sometimes if the chain isn't kept lubed it'll develop dry or stiff links, meaning the chain doesn't track freely over the sprockets or if its really worn the teeth on the sprockets can get hooked and catch on the chain, but this is normally on more powerful bikes.
Alternatively you might have a loose front sprocket, so whip the cover off and see if the lock nut is good and tight, at the same time check to see if theres any play in the driveshaft, a little bit of in and out is ok but side to side would be bad
If that doesn't at least find the problem you might have to start looking elsewhere!! best of luck!!

thanks for that mate! I went over the chain and sprockets last night and although the chain isn't pulling away from the sprocket at the back, there's a lot of play on it, it looks like it's been knocking against the centrestand when there's a change in the power being delivered to it, time to adjust the chain by the looks of thing I'm glad that's an easy job as I'd been bricking myself about having to replace the gearbox for a while there...


As for the scooter issue, they've never had any appeal to me, they just don't look as fun as bikes. That said, I've never ridden one so it's quite possible that I might have a go one day and think they're the dogs bollocks, I'm only having a bit of a rib with it

[howdamnhard]

Glad you got it sorted out. Hope it isn't another original equipment chinese made chain. They stretch very quickly,so check weekly. I replaced mine with a decent one and only had to adjust it once thereafter. Adjust as per manual.After you have adjusted it , sit on it and check it isn't to tight.