Took my 650 out for a good workout this weekend. My friend was riding a honda and had no issues. My cat did fine too...until a couple hours in. It seemed fine and then just kind of died. The more I throttled, the quicker it died. Almost like it was flooded, wasn't getting air, was choked after warming, or something like that. Anyway, after letting it set for probably a minute, it was fine again and rode perfect for another 10 min before doing the same thing...died, revived, and then went a while before the same thing.

Any thoughts???

 

Sounds like a fuel issue. Check the tank vent and make sure its clear, both hose and the nipple in the tank.