I've put about 100 miles on my rebuilt 92 XR600R. The only problem I've noticed is very hard hot-starting. Cold starts are 1-2 kicks but some hot starts take 10 minutes, and 20-30 kicks. The bike is being stopped normally. I'm also getting the occaisional backfire and kickback (not at the same time) when trying to start hot. The bike never did that before. During the rebuild I did have the camshaft diassembled to replace the automatic decompressor cam. I don't know what my carb is jetted to (it has a quiet Cobra ISDE exhaust) but it has always belched black soot when I start it up. Any suggestions? Mike.