Chafing/grinding noise

[Rikki]

As title suggests I'm getting weird noises coming from somewhere. Don't think it's the engine as it sounds fine when stationary. Usually starts happening at around 20mph. I thought the front mudguard may have come loose but it seems fine & there doesn't seem to be anything stuck under it. Chain guard hasn't come loose either. Can't think where else moving parts might not sit flush. The noise is getting louder & louder to the point where even pedestrians are turning round to look. Could it be a wheel bearing? There doesn't seem to be any adverse effect on handling at the moment but getting very worried about taking it out. Any ideas anyone?

[bandit]

Check the chain condition/tension/sprockets hope that front one hasn't loose.

[darrsi]

Calipers okay?
Not got a stuck piston causing pads to rub on the disc?

[Rikki]

Don't think it's the brakes binding as I cleaned them a few months ago & they're still nice & sharp.

The chain tension seems ok. Is there an easy way to check the front sprocket as I would need to replace the gasket if I took the cover off? I guess it's possible there could be some debris under there though. I have found a few bits of grit lodged in places on the outside of the engine.

The noise doesn't really sound like metal grinding though, more plastic-y if you know what I mean.

[Fazerider]

You don't happen to have a Bridgestone BT021 on the front do you? They're renowned for making a strange abrasive noise.
The easy way to check the front sprocket is to take the cover off then, when you're done, scrape off the remains of the old gasket and refit the cover without it. You might need to adjust the clutch slightly as the mechanism that shoves on the clutch push-rod is now a bit closer to it.

[Rikki]

Took the sprocket cover off, cleaned out the kilo or so of accumulated filth, degreased it & put it back. When I took it out for a ride the noise was still there, so took it to the bike shop today & on the way there it quietened down. When the mechanic took it out for a ride the noise had totally gone. I think it must be haunted.

[darrsi]

It's not your leather trousers chafing on your seat cover? 

[ChristoT]

It sounds suspiciously like the problem I had - take the front wheel off, and check the speedo drive is well greased. Mine wasn't, and made a very distressing sound at about 40mph. Attacking it with grease solved it. Hope that's all it is! 

[Rikki]

If my trousers ever make noises like that I'll start praying! 

I've read about speedos making funny noises on another thread before, and it certainly was 'distressing' but as it seems to have disappeared I think I'll leave the front wheel alone for now. May resurrect this thread again if it comes back.

Cheers for replies all.