I have had this bike for 3 years. Over the winter I made a few small changes that turned the bike from sluggish and un responsive to crisp and powerful. the bike is much easier to ride now, because the power is so predictable and always there. Pulls beautifully right off the bottom. I am rarely using the clutch out of corners now. Last summer the bike had V-force reeds, fmf fatty with powercore silencer, stock plug, and 93 octane mixed with honda full synthetic. These are the changes I made 1. cut 3 inches off of the powercore silencer. 2. ngk br9eix sparkplug 3. installed s8 nozzle in carb. 4. Iam running torco 110 fuel. since I did all these changes at the same time without testing inbetween I cant say which changes affected the bike the most, but it runs perfectly now. My jetting has always been 400 main, 40 pilot, 38-70 needle, and 1st or 2nd clip on the needle. the airscrew is touchy I soldered a small piece of wire with a 90 degree bend onto my airscrew so I can adjust it without tools on the side of the track if necessary, although it is alot less finicky now. I got some useful information on this site when tuning this bike and am relating my experience in hopes that it may be helpful to someone else.