ok so here is the deal, my friend has a '99 mxz 670 ho. nice sled cant complain much there esp since he only payed 500 for it. this sled is using 1 tank of oil everytime he fills his gas tank. i am not possitive, but i told him that doesnt sound anywhere near right. could anyone tell me how much oil should be consumed per tank of gas, or maybe enen what the mix ratio should be? any help would be greatly appreciated.

I have a 99 Summit X 670 HO, they do use lots of oil but it sounds like yours is using about twice as much as mine. It does get expensive and I run full synthetic or as a minium synthetic blend injection oil. You should be able to talk to a dealer to find out how to adjust the oil injection. The 670 is a great engine but almost every one took the pto bearing out. My sled has 4500kms since the bearing was changed and the engine rebuilt. (Skidoo has a special grease that you pack the outside pto bearing with and you shouldn't have any more problems) If you run NGK BR9EIX spark plugs you should never foul plugs.

thanks for the info, i will pass it on to my friend