My F7 blew the Mag side piston on Saturday at about 100 miles on the sled. I was running the road on the way to my first trail of the year. The sled had been bled twice and at 20 miles I found one air pocket as the coolant bottle was empty. I refilled and didn't have any further problems(and bled it again at 60 miles). The coolant level never changed again so I thought I was okay. I always checked my running boards(except for my final ride(I guess the air pocket moved up to the head causing the pump to cavitate)) and they were always warm. Sure enough once the motor seized I felt the running boards and the right was was stone cold. Thankfully I was paranoid of the thing blowing up so I brought along a tow rope and had the indignity of having an RX-1 tow me home. I was pissed, as I was up for the week and my kitty was hurt. Because of New Years the dealer was not able to get parts until today, but I had to come home anyways. I was forced to ride RX-1's all week. Great motors, but they are absolute tanks in the tight twisites. I almost traded my F7 on my old ZR from last year which wasn't sold but decided to gove the F7 one final chance. If it blows again it is gone. I've had it with being an Arctic Cat test pilot. They should never have released this sled without doing further testing. Did they actually test this sled in the snow with the new heat exchanger? Luckily Cat has all the parts so I won't miss any more riding time.