Ok here is the deal. I just got a 00' 650L. And it is a DOG. It will only wheelie with the clutch in 1st gear. The guy said he had the Honda deal remove the smog pump and dring the carb slide and rejet as they recommned "on some popular thumper website" LOL I asume he is talking about Daves mod. I already have on order: Tag bars, UNI air filter, FMF Q2, Eibach springs front and back. RK XSO chain, and steal sprockets 14t, 46t. Hoping to get a Clarke tank soon when I decide on the size. I hope these mods help it a lil. Anyway back to the question at hand. I want to add a 1mm Bore with a 10.5:1 piston, maybe some port and polish work. Mike at XR's only said the best bang is to run a 10:5 piston and port and polish. He said that Hotcams have longegivity issues and just move the power curve not increase it. He said that 1mm over is plenty and more reliable than going any larger and I wont see a diffrence. He said with this set up with air filter/pipe, I should be @ 50+ rear wheel HP. Anyone else with any of these mods care to chime in? I plan on ordering new valves, timing chain and a piston kit and gaskets this weekend. The local shop can port and polish for 300-400 bucks. I plan on rebuilding it my self. Anyone go with a higher comp piston w/o port and polish?