Hey guys,

I gave my bike a good cleanup lately, which involved me taking the rear sprocket off. I then put the sprocket back on afterwards and hooked the chain onto it and yesterday when I checked, some parts of the chain were as tight as the Virgin Mary herself, while some parts had a bit of give in them.

The chain is the best one I could find at my local shop (RK GB525GXW) and has only done about 1000kms.

When I tightened the chain before I took the bike apart, it had the same movement the whole way through. Perhaps I've hooked the chain onto the sprocket wrong?

Should I move the wheel so that the loose part is at the bottom and then try to move the chain up one tooth?

Cheers

Only thing i can think that youve done is put the sprocket on backwards but that shouldnt make the chain go tight in places, you cant really put the chain on wrong, well i dont think you can anyway

You need to put the chain on so the same amount of links is up the top as at the bottom (front and rear sprockets are directly adjacent), if you know what I mean.

Drunkn Munky wrote:Only thing i can think that youve done is put the sprocket on backwards but that shouldnt make the chain go tight in places, you cant really put the chain on wrong, well i dont think you can anyway

Nope it's definitely not backwards.

Cammo wrote:You need to put the chain on so the same amount of links is up the top as at the bottom (front and rear sprockets are directly adjacent), if you know what I mean.

Hmm I think you're confirming what I was thinking. I think when I put it on I made it so it was tight at the top and it had some movement on the bottom. But I guess now when I think about it it should have the same amount of give on the top line as the bottom line of chain..

Cheers :)

OK, so I've played around with the chain on the sprockets and can't get the problem rectified. I've done some reading and alot of guys on the Thumper forum seem to think this can be caused by the sprocket not being perfectly round.
http://www.thumpertalk.com/forum/archiv ... 82728.html

By my calculations, the chain is about 115 links and the sprocket is a standard 38 tooth which means the chain goes around approximately once every 3 revolutions of the rear wheel. So maybe I should go see if the tight spot is visible once every revolution or every 3 revolutions to see whether it is the chain or the sprocket.

The chain on the bike when I bought it looked in good condiiton, as did the sprockets. However, it was replaced by RB Imports because the chain was loose. So since this is the strongest 525 chain available and has only done about 1000kms, and the old chain looked pretty good to me when it needed to be replaced, and the sprockets still look reasonably new, maybe the sprockets are the problem area?

The Thumper Talk thread suggests that some brands of sprockets can sometimes not be perfect and cause this problem. Perhaps I should try a different brand of sprocket this time.. And hope to god the sprocket is the problem and it hasn't stretched my $280 chain!!

Any ideas/comments?
edit: last week when I pulled my bike apart I may have got the tiniest bit of degreaser on the chain but I washed the chain off straight away. I don't think would have caused the links to be weakened and stretch in 200kms.. I guess if I see how many revolutions of the rear wheel it takes for the tight spot to appear I can figure out if it's the chain or the sprocket...

EDIT 2: just checked and the tight spot is appearing once every revolution of the rear wheel so it's either the sprocket or there are 3 tight spots in the chain (very unlikely). So maybe the rear sprocket isn't perfectly round and I should replace it with one of a different brand? Might as well replace the front one too huh?...

Thoughts?

Rule number 1, replace C+S as a set. Ok this isnt 100% nesersary but your putting a new chain on worn sprockets that have worn to the old chain.

In my younger 125cc days i was constantly going through chains and sprockets as i didnt have the cash to replace all 3 at the same time, it always caused problems.

have you checked the rear hub outer bearing had a similar problem getting chain tension correct with a new c/s kit turned out outer bearing was feked completely.

What size front sprocket are you using, sometimes the ratios of the sprockets can cause uneven wear this may also cause a tight spots in the chain.

Drunkn Munky wrote:Rule number 1, replace C+S as a set. Ok this isnt 100% nesersary but your putting a new chain on worn sprockets that have worn to the old chain.

In my younger 125cc days i was constantly going through chains and sprockets as i didnt have the cash to replace all 3 at the same time, it always caused problems.

Yep I've always thought this but when RB Imports told me I needed a new chain because it had a tight spot, I asked them if the sprockets need replacing and they said the sprockets were fine..

skinnydog0_0 wrote:What size front sprocket are you using, sometimes the ratios of the sprockets can cause uneven wear this may also cause a tight spots in the chain.

Standard size sprocket.

davethetrucker wrote:have you checked the rear hub outer bearing had a similar problem getting chain tension correct with a new c/s kit turned out outer bearing was feked completely.

hmm what is the rear hub outer bearing?...


Thanks :)

1 question...why r u running a 115 link chain on your 35? have you changed the size the of the standard sprockets?