Snowmobile Repair: 488cc polaris engine problems, polaris engine, hello art

Question
I own a 1996 Polaris Classic Touring 500
488cc. This machine has 6700 miles and is blowing wholes in the top of the pistons thus needing two pistons etc as it scuffed cylinder walls resulting in having the cylinders bored etc etc. so professionally repaired back out same problem hole in piston on the water pump side other piston appears ok but will need two again as it scuffed walls as well-- frustrating what is causing overheating I guess is the question?  

Answer
Hello Art,

  Many things can cause this problem, but it is an issue of localized overheating of the upper cylinder and head area. Here is what I recommend. Be sure you are using spark plugs of the proper heat range, they are NGK BR8ES. Another thing that may be causing this is the fact that the oil pump may not be operating. Another thing to look at is the possibility of the water pump not operating. There have been cases of bad CDI boxes being linked to engine overheating. If the engine timing is off, and the plugs are firing too soon, this can occur. Something else you may want to take a look at would be the seals. I would imagine that you will replace them when you rebuild the engine. You may want to rebuild your self so that you can tell for sure what is going on in the engine. Last of all, the people the rebuilt it should give you warranty service, if the work they did was recent. Otherwise, you may want to take it to a certified Polaris Dealer. If you need parts for the machines you can get them here: http://216.37.204.202/polaris_oem/PolarisSnow.asp?Type=12&A=58   and here: www.denniskirk.com  , for a decent price. I hope I have helped you. let me know if you have any other questions. Good luck with the sled! --Arcticatman