My 2005 Grizzly 660 cuts out in the following situations:
1. When the engine is hot (30 minutes of rough riding in and out of 4X) and 4X ing up hills. This is VERY spooky when almost verticle and the engine cuts out. I've never rolled it, but been very close.
2. When it's hot and in differential lock- usually when I initially hit he gas.
3. When I'm going through rather deep (just below seat) rivers or water- again rather scary when you look down river to see your fate.
I know it's not bad gas. I have had the heat protection "upgrade" done, but don't know if it's enough. I suspect it has to do with boiling gas.