I HAVE A 2001 SCRAMBLER 400 4X2 AND SOME HEAVY MODS WELL THE PROBLEM IS THIS IT SOUNDS LIKE THE CHAIN IS SLIPPING WHEN I GAS IT BUT ITS NOT THE REAR CHAIN(OPPS CAPS) took off the gear case and everything looked fine but the chain inside seemed a little strecthed is this very common problem should i replace the chain and gears? or is there something i am missing?

 

They do tend to stretch. It might be a good idea to change out the chain. You looked at the rear sprocket and made sure the teeth are not rounded of or chipped off?

 

Any time you take a gearcase apart it is a good idea to change out the chain to be on the safe side.