Yall can call me a traitor but I just sold my 2004 Grizz 660 to buy a BF, but I had the same problem. Wheelies, bottom end hesitation and the engine being mounted so far forward. So I took on the aftermarket scene: HMF full system, Moose Utility Stage 1 jets, and K&N. Which all helped with awesome power and great sound but still hard wheelies and grunt bottom end. I changed out the RECITIFIER--WOW, now wheelies were easy, just sit on the seat normal and punch it, hang on, and don't let it go to far cause it would, I could not pull easy 4-5 links on the mighty 700 prairie. Go to Procom Engineerings website check it out www.procomengineering.com, they have a high performance rectifier and high performance CDI which makes the top end pull alot harder.[img]i/expressions/face-icon-small-happy.gif[/img]