replacing the chain

[Guest]

How do I know when it needs to be replaced?  A friend of mine recently told me it was stretched.  (it looks fine to me...ha ha)  I have 9900 miles on the bike.  He also said if I replace the chain I should replace the sprockets too, anybody know if that's true?  I'm still learning all this mechanical stuff.  

Thanks,
Kris

 

[africanrider]

if you find that the chain needs tightening every 200 miles or less, thats a good sign it may need to be replaced. The slack should be about an inch or so....and I'd suggest that when you get a new chain you get new sprockets too....sometimes you may find that one set sprockets will actually last the life of two chains, however, you risk wearing your chain too soon by running it on worn sprockets...

most chains will last about 12000miles, sometimes even more...as long as you lube the chain often say for example, everytime you go through a full tank of gas....just my .02 cents

 

[Mikey D]

Several ways of checking the chain...

1. The technically correct way is to count links and then measure the length of the chain when it is stretched out straight.  You can find the # of links and the specific length and tolerance in the Busa manuel.

2. Quick and dirty.  Grab a link on the back side of the rear sprocket and try to pull it backwards.  It should have a small amount of play, (Less than 1/8") if it significantly moves off of the sprocket (1/8" - 1/4"), it needs to be replaced.

3. Quick and dirty.  Grab 2 links next to each other, keeping the links straight with the chain, push them together and pull them apart.  If you can notice movement between the side plates of adjacent links (keep your eye on the gap between the side plates on the adjacent links) the chain needs to be replaced.

Check your sprockets.  You'll notice thet the tip of the teeth of the sprocket should have a small champher at the top, this should be symetric on the front and back of the tooth.  As the sprockets wear, the tooth will wear on the back side of the top of the sprocket and that champher will dissapear.  
Look for:
- any asymetric wear in the teeth.
- any hooking in the teeth
- bent teeth
- broken or missing teeth

Any of these conditions necisitates replacing the sprockets.  Be sure to inspect the front sprocket as well as the rear.

BTW - Chains don't stretch as in the side plates get longer.  What happens is the pins under the rollers get grooves worn in them allowing the side plates to move back and forth.

I keep promising to post picts of this.  I'll try to find the old one at school tomorrow.

Hope this helps.  Good luck!