We have a 2004 kfx 80 and never had any problems. Just noticed this week that the rear end is shaking (you can move the rear end a little from side to side with your hands). Is this the bearings and is it easily fixed/replaced? Thanks for any input.

 

My guess it would be the bearings you need to replace. Sometimes you might have a little problem depending if it was ever taken apart but, fairly easy. Make sure you dont ride it like that as you could destroy the carrier in the rear. The bearings should be about 30 bucks.