I purchased an '86 Honda XR600 when my son outgrew his Honda XR100 and claimed as his own my Yamaha RT 180 (which was probably underpowered for someone of my nearly 300 lb. girth anyway). I was originally looking for an XR400, but there were few available locally and there was a comparative glut of XR600's, so I decided to go for the big one, and it is much more pleasurable to ride a bike with power to spare. However, the gearing seems very high. For example, I can ride all day in first gear (occasionally second) on trails that would have had me (and now have my son) in second or third on the RT 180. On the XR600, even first gear seems too high for some of the tighter turns, etc. (Though it seems to have low-end torque that is unending). The prior owner was going to make the XR600 street legal, but decided not to. I think he put an aftermarket rear sprocket on the bike and that is the reason for the non-trail friendly gearing. Any suggestions for a sprocker replacement or other fix? While I'm at it, the Supertrapp exhaust the prior owner installed is louder than I would like. I reduced the number of disks from 12 to 6, but there was not a significant difference. Should I go to 3 disks, or repack the muffler? If repacking is suggesting, what shoud I use?