Snowmobile Repair: fouling plugs, br8es, sled

Question
skidoo 2001 mxz 440x- sled has racing heads, compression is 150 lbs, changed jetting to 270 and running oil 3-1. Problem is after running sled and shut sled off when you start the sled back up-the plugs foul.Have cleaned carbs, adjusted floats, etc.....Any suggestions?

Answer
Hello Rob,

 I think the only thing you can really do is either try a high quality fully synthetic oil like Amsoil Domminator, or try hotter spark plugs, such as NGK BR8ES. Sometimes doing mods to sleds will have this type of result, and it takes alot of diagnosing to cure it. Let me know if you have any other questions. Good luck with the sled! --Arcticatman