chain and pipe problems cr 250

Get a 120 link chain and have your local shop cut it to the necessary length. Depending on your sprocket combination, a stock length chain might not fit. What sized tire are you running? 110/90-19 is stock. A little rubbing is acceptable. The joints between the pipe and muffler often leak, many of us ignore this. Your dealer will be able to tell you what seals you need in there. Is the chain coming loose because the tensioners are moving or is the chain stretching? Chains get longer as they wear so you do need to tighten them periodically. If you aren't lubing it properly or are riding in water/mud, your chain will wear very quickly and will need to be tightened every ride and sometimes more often. If you don't want to have to keep adjusting your chain, you should invest in an o-ring chain.

make sure you dont need new sprokets..Most of the time when you replace a chain you should change out sprockets,both front and rear...you can even play with the sizes...for more low end power add a few teeth in the rear...I went from a 51 to a 53 on my kx 250 05 and I love it for sx...and for mx its ak just uses higher gears ...