I have a black f-7 sno-pro with standard graphics. Mine blew up after 190 miles. I was riding in the Big Horn mountains of wyoming, elevation was 8,300-10,000 feet. I put 56.5 gram weights in the clutch.With stock gearing. the sled performed wonderfully. I was riding with my buddy who also has an f-7. The first day we put on around fifty miles, mainly deep powder riding and hill climbing. The sled performed great, it had a slight bog if you let off of the gas and then nailed it again, which seemed to get better throught the day. the second day we rode 150 miles, combination trail and boondocking. The sled ran great. The last day we were there, we made it six miles from the lodge then it happened :huh: we were going down the trail just cruising, around 6000rpm 40-50mph. I went to hit the gas and there was nothing there, the sled just died and coasted to a stop. I was able to get it started on more time but it was running rough. It sounded like I had fouled a plug abd it was running on only one cylinder. I pulled the plugs out and the clutch side was nice and tan and dry, the mag side was dark and wet with little dropplets of antifreeze on it. When I got home I took the sled to the dealer. They replaced the cylinder and piston on the mag side put new rings on both sides, and replaced the crank seals. the piston looked very bad heavy scuffing on both sides. Arctic Cat is telling the dealr that it must have got hot. (i.e. air bubble) The dealer also found a bubble in the oil line, which I know was not there before I checked, He said that the check valve in the oil reservoir cap may have gotten stuck closed, not allowing the system to breathe.the sled was also never tipped onto the mag side. I also went through and did the burping procedure three times prior to going on the trip. The check engine light never came on. Iwas running AC APV oil, and regular fuel. :wacko: I get the sled back this saturday I can't wait.