Snowmobile Repair: Motor repair, air leaks, cylinder walls

Question
I have a 98 Ski-Dont 380, Touring E. This past winter I burned out pistons 3 times. It alternates back and forth between cylinders. The lower seals appear to be okay.  I was meticulous in checking carb connections for air leaks.  The problem has occured each time after a flat out run.  Am I asking to much of the sled or have I missed something.  The first 2000 miles were problem free.

Answer
Hello Dave,

  I can almost guarantee that it's the seals in the sled. you might want to replace the bearings as long as you have it taken apart, too. The seals on the Doo's in the time range are not the best, and will do exactly what you have described. Also, you might want to make sure the cylinder walls are OK, and haven't gotten scored from the piston failure. The sled should be 100% good to go, with new gaskets, seals, and bearings if necessary. Also, you may want to consider running Amsoil Synthetic, like the Interceptor type. Those motors are pretty small, and work real hard, so heating up can be an issue. Hope this helps! Let me know if I can help at all, with any other questions you might have. Good luck with the Doo! --Arcticatman