What kind of squish are you guys with machz's running that have eng. mods such as trail porting reeds and spacers big carbs , pipes? I tried .062 and melted fast 2 of 3 pistons with pump 94? And at .070 its fine but the rings flake after 500 miles or so and eventually break and tear stuff up ? Is something appearently wrong or does this just go with ported cyls. I have had people look at the chamfers and say their fine? I just want to be more reliable is this possible?

look at the width of the exhaust port as a % of the total bore, is it over 70%? someone might have been greedy with the grinder

what about timing?

dynoport did the cyl's but the exh. port is not widen much , also timing is stock.

what pistons are you running, type, brand, size???

coated ski-doo pistons /rings std. bore

crank seals? warped case? Not getting all the air out of the cooling system?

My gut thought is where are the egt`s at. Maybe a anomally where the wash and plugs are ok but your cookin. I`ve had sleds , and still doo, that I can go up 2 sizes and S&IT dont look much different, but I only run 500`,.... ,and I dont have egt`s....Just for its and gigls see how far up in jet you can go before performance drops off. Could the flaking and the melting be too different problems?, unlikely but, lack of oil I would presume could cause a flake problem. I had a mach zed, ran it at .060. I never melted a piston, the guy that bought it ate em, whats up with that??`

I pre-mix the oil so I know it gets 50:1 for sure , ring flaking has been an issue and also with a friends thats ported more than mine? Maybe I need to run it on the rich side ?