I have raced 4 H.S. on my 2010 and the first 3 I thought my arms were going to fall off, due to the massive low end hit. Way too much for off road. This past weekend I raced a MSXS in TN, and my bike was awsome this time. I put an FMF Q silencer, remapped the cumputer to Fuel Injection (FI) +4 +4 -3 +4 +4 -4 -3 -4 -4 Ignition (IG) -3 -3 -3 -3 -3 -0 -3 -3 -3 And put on a Gytr flywheel that added 4.5 oz of weight. This made the bike smooth and controllable off bottom. This is the best bike I had by far now. cant wait tell the come out with an oversize tank. then it will perfect.