I've been using mobil 1 MX2t for the last few years, I like it. Runs clean, no spooge, very little carbon build up in the top end after rebuild. Top end parts looked pretty good considering it had about 100 hrs on it. :ohmy:
It's awesome. Very reliable, and very smooth power, but very powerful. I Just ordered a FWW to hopefully tone it down a bit for the woods. Top ends last much longer now, back tires don't. I've been running the 74mm bore for about 4 years now. Just pulled out my original 310 piston.