Quote Originally Posted by jgixxer1
What gearing and how much time on the head work? Have a friend in the market. I sent him this link.
Gearing worked at IMI and at Pueblo. No idea what the rear is but I could find out. The front is (I think) a 15, or whatever the biggest one you can run without cutting the cases. Bartman could tell us which one that is...

The 2006+ (I believe?) heads used the larger valves but are a direct bolt on. So instead of redoing the original head, I bought an entire new head with a "Level 1" port. It is a mild prot that really just opens it up a bit and unshrouded things. It was a noticeable difference over the original 2003 head however. The headwork was done in 2007(ish), and has a bunch of IMI time on it and (1) MRA race weekend at Pueblo.

There is no slipper clutch, but I am used to riding twins so I don't rev the shit out of things. This is the opposite of a YZ450; it falls on its face up high but pulls like mad down low, so short shifting it actually is faster than rev'ing the piss out of it and I never worried about top end time due to that. Of course, YMMV as these things have popped in the past, but mine (and Barts and everyone else I know who doesn;t build the snot out of them) have had no problems.