I am starting to go thru my sled and do some work on it before the snow falls. I will be tuning up the carbs and syncronizing them. One thing that I thought about doing this winter was run some carb cleaner thru the gas. Is this safe? I have heard that they tend to ruin o-rings and other things. What would be the best to use? Also, while I am tuning up the carbs what do you think about me removing the heads and cleaning them? Some people have told me that they have done this and their sleds run much better after doing so. I have also heard that when taking it to a shop to get a tune up that they can do this also but for a nominal fee. What do you guess think?