So if an o-ring falls out of my chain when I'm cleaning it, is that a bad sign?

[SeriousGeorge]

Well poop. I knew my chain was pretty much on it's last legs, but that pretty much sealed it. May as well just do the sprockets and change the gearing while I'm at it. As long as I'm doing that I may as well replace the rear tire that's flat as a board in the center. Man, this stuff just keeps adding up. 

Is there any reason no one seems to change the teeth on the rear sprocket? Everyone seems to go to the 15 tooth on the front, but no one seems to change the rear. Any potential issues with clearance on the chain guard or anything else going to a bigger rear? The PO put 80 series tires on and I'm probably going to go with the Avon AV45/46 combo when I replace them so it'll be just a bit taller still. I was thinking of going to the 15 tooth front and maybe going up a couple teeth in the rear. Any issues with that? I rarely use the freeway and most of the time my max speed is 65mph.

[MarkusN]

Going up on the rear sprocket is technically the better solution (no clearnace issues with the swing arm; check the chain fender, though; lower forces in the chain.)

Possible reasons why it's not done so often: The rear sprocket is larger, thus more expensive. You have to change chain length as well.

[scratch]

You can safely go to a 43 tooth rear without having to remove the chainguard (you can go larger but I don't know how much); a larger sprocket gets the chain off the chainguide on top of the swingarm near the swingarm pivot, reducing wear of the chainguide.

Going up one tooth is not enough to warrant going up 2 links on the chain, though; you can only adjust the chain by an even number of links (for every outside pair of links there has to be a corresponding inside pair).

[SeriousGeorge]

Cool, thanks for the info. I'll probably go to a 43 tooth in back and keep 16 in front then. That should be a little easier on the chain and be enough to compensate for the taller tires plus just a tiny bit more. Do you think 112 chain would be enough or am I going to need to with 114 links?

[scratch]

4 teeth larger than stock; I'd go with 114 links.

[SeriousGeorge]

Thanks again scratch. Now just gotta convince the wife I need to spend some money.