I bought an 2004 XR650L at a good price (bargain) with about 2k miles on it, with a few mods and running like shit. In fact, it would only run on the choke for the fist 10 to 15 minutes and not very well after that. Going through it I discovered that it had no screens on the fuel petcock, carb was full of crap and the stock pilot jet plugged. I added a fuel filter, cleaned the carb and added a 55 pilot jet. Bike is equipped as follows: Full Big Gun exhaust (not sure which one) with sound diffuser in place, Dynojet jet kit with 165 main, needle in 3rd groove, 55 pilot, dynojet kit slide spring, slide not drilled, mixture 2 1/2 turns out, K&N air filter, de-smogged, de-snorkeled, 14/48 gearing, new o-ring 520 chain, stock tires, lowered seat foam, and forks lowered a bit in the triple clamps. Now, I'm not complaining at all....I've got it running and it idles and runs great with best throttle response I've ever experienced from a thumper. But I've read some threads on here about owners with similar mods describing full on first and second gear wheelies, having a hard time keeping the front wheel on the ground etc. Not the case for me....maybe a few inches in first if I open the throttle quickly. Am I missing out on some power here? From the descriptions I've read I was expecting something like my old KX250 dirt bike that would wheelie in first, second, and third if it could find the traction. Any thoughts or ideas? Is my lowered seat foam and lowered forks affecting the center of gravity enough to prohibit wheelies? I'm 5'7" 160 lbs. Is the sound diffuser robbing me of some power? Drill the slide and add a bigger pilot jet?