Scraping noise coming from transmission - gsxr250

[Jase W]

OK, over the last week or so i've noticed a slight scraping noise coming from the transmission whenever I'm decellerating. The other day I tightened my chain because it was really loose, and now the scraping noise is alot worse. The only times it seems to go away is whenever the bike is under positive throttle. When I move the bike forward in neutral, there is a clicking noise coming from the front sprocket.

Can anyone give me some clues as to what this could be? I though the sprockets may have been out of alignment so I checked that just now, but I can see anything wrong...

I dont really want to take it up to the trackday if the trans is on the verge of giving out.

Any help would be greatly appreciated.

Jase.

[MSTRS]

Take the chain off. Run the engine in gear. If noise is gone, get a new chain and/or clean around front sprocket (remove cover to ensure nothing caught in there). However, if the noise still there then ?????? trouble
EDIT: just struck me that trouble could be a collapsing bearing on the final drive?

[Jase W]

I dont have the equipment or knowhow for taking the chain off so we can scratch that idea.

Basically I would like to know if this is a serious problem and whether I should risk taking it up to taupo on sunday or not.

I realise its hard to tell without actually seeing the bike but if this has happened to someone else then maybe they could give some insight?

Cheers

[MSTRS]

I dont have the equipment or knowhow for taking the chain off




Take it to a mechanic then. I wouldn't ride 600+ kms like it is without getting it checked at least

[Ixion]

..
EDIT: just struck me that trouble could be a collapsing bearing on the final drive?

Yeah, that would sound quite a likely call to me. Clicking could be broken balls in the ball race. And it was worse after tensioning the chain because the greater tension is pulling things more out of line. On accelration thrust is reversed, guess it doesn't scrape that way.

Suggest OP gets someone knowledgeable to look at it ASAP. In theory a collapsed output bearing could cause a transmission lockup. Not a nice thing to have happen at speed. Only ever had one, once, don't ever want another .

[Coldkiwi]

make sure you haven't over tightened your chain too. roll it around to see where the tight spot is and tighten it there (20 odd mm of slack with no load). If you tighten it at the tightest part, that may over stress an already rooted chain which could cause it to snap (about as much fun as it sounds!).

like Ixion said, get it to a shop to have a qualified mechanic look at it.

[Jase W]

ok i'll have to take it into the bike shop at some stage. the only problem is its my only method of transport and i need to get out to jville on it till thursday... arghhh. :angry2:

[Coldkiwi]

How far to the shop? If its not too far, you should be ok, just take it very easy

[Jase W]

the shop is in the cbd but thats not the problem... i need to take it from karori to jville everyday until thursday. not to mention the trackday.

i just keep having problems that prevent me from going to the trackday... perhaps it just wasnt meant to be...

[Jase W]

I'm gonna take it in to WMCC tomorrow morning and they'll have a quick look at it, then i'll take it from there.

Thanks for the input :D

[MSTRS]

Wise move. These sorts of things can end up being VERY expensive the longer they are ignored.

[Jase W]

Ok I had tightened the chain too much, so nothing major. But its rooted anyways (not because of me overtightening it - just from age), so that & the sprockets need to be replaced - ~$350.

Wont be getting done till sometime next week though so I dont think it will be wise to bring it up for the track day :( :( :(

Just when I thought i'd be all sorted to come up too :(

[XTC]

$350 for chain and sprockets sounds a bit steep to me. If you were up here I'd tell you to buy them and i'd fit them for you. That would save you the labour cost at least. Anyone willing to do that for you in Welly??

[Jase W]

Well its $270 for the parts and the guy reckoned 1/2 hour of labour... so i'd get charged a full hour which comes to $330

[inlinefour]

For 350 bucks I'd be expecting some pretty high tech gear. Check out the local engineering wholesalers. Not only do the ones here do sprokets and chains, but the last chain was a DID chain for very little $$$ :niceone:

[MSTRS]

Gold-plated, 620 'O' ring is it, with titanium sprockets?? Shop around.

[GROOMER]

Check with motomart...my chain alone was fairly cheap, dunno bout rear sprocket though

[FlyingDutchMan]

I got new sprockets and chain fitted sameday for $225. $350 is wayyy too much.

[Jase W]

Ok i'll get in touch with motorad & motomart, see what they charge...

[vifferman]

Is this a timely time to post this link? (It's about chains and like that there...)

http://www.quality-cycle.com/truth_about_motorcycle_chains.htm