i used the search feature 1st but didn't come across anything. i don't know exactly whats going on but my chain as you spin the rear tire goes from loose to tight loose to tight. im not sure what to do about this. figured id start here.
I'd be replacing the chain right away as a portion of it is obviously stretched. Have a really good look at both sprockets as well. Chances are they need replacing too.
As long as you aren't getting fancy sprockets and chain, the cost is really not too bad. The problem comes if you don't have a chain tool. That is where the real expense comes in.
I picked up a motion pro break and press tool for $60 at a local dealer...
don't need a heavy duty one as we only have a 520 chain...
you can go really cheap and just get a press, then dremel off the old chain (assuming you already have access to a dremel, grinder, etc....)
I basically worked with a bunch of other riders... we all pitched in for this and our tire changer... saves money in the long run... even if we didn't go in together on it, I was going to get this stuff to have.
18k on a chain is pretty good lol. Time for a new one like they said. And if you don't have the chain breaker kit you can always use the clip style mater link. I've never had any issuses what so ever with clip master links.
www.Solomotoparts.com give us 10% off. Contact Tyler, he's the man! They have a nice light weight 46T rear sprocket. Contact him... Last time I spend around $180.00 for 2 sprocket and chain. But I went fancy black chain.
There's some good advice here. A tight spot on the chain is not "game over" however. If the chain hasn't stretched to the end of the adjustment range, then work on it. A locked link can happen for so many reasons.
I'd suggest you put the bike up on a rear paddock stand. Use everything at your disposal to simply clean and lubricate the chain, especially that link, and get it to work again. Pull the chain if necessary. Soak it in oil, if you think it will help.
If your sprockets aren't wearing, and you've simply got a stuck link on a good chain, then do what you can to fix it, before you buy new. A locked link is bad. If you can't fix it, the chain has got to go. I wouldn't jump on that boat until I've tried, though.
Upwards of 15k and some have gone 20k.... Just keep it clean and lubed, proper slack and not out of alignment. I would not know from experience though. I usually wreck or sell before then.