I have a 2007 YZ285F that I am trying to get the jetting right on. The motor was just built by me not too long ago and has less than 5 hours on it so everything is mint. I was going to run stock jetting because it seemed to work a little better during the colder months, but now that it is warm outside it blubbers and bogs on the bottom end. Once it gets past that into the top end it just flat out hauls ass. Heres whats done to the motor... Balanced/trued/welded Hot Rods stroker crank +3mm MXtime recut my valve seats and rebuilt the head New Titanium OEM valves/springs/seals New Hot Rods Stage 2 cams (both intake and exhaust) New +3mm Cylinder Works cylinder New +3mm Vertex piston Stock exhaust Not sure what jetting is in there right now but lets assume its 07 YZ250f jetting. If its anything like jetting a 2 stroke, right now to me it personally feels rich on the PJ but its not hard to start after a fall.