Ok I have a few questions here for my zrt 600.. First of all, I too am having that problem that when I first get it started, which only takes about one pull cold, it revs up to 3 - 5 rmp for about 2 to 4 minutes and than idles back down to a low 1 - 1 1/2 rmp. I also noticed a small wet spot under the middle pipe, im thinking it may be snow. It also uses a ton of gas, I refueled it last night and rode it like 3 times today mabey in between 10-20 miles and the damn thing is already down to half a tank. I also noticed when its parked in the shop where I usually start it, the exaust is kicking out a ton of oil, I let it idle for 5 minutes there and theres a solid black spot right at the exaust. I put my hand under it to confirm it was oil, I wonder if its running to rich? Also My speedometer isn't working, the guy I bought it from replaced some weather guards or something behind the 3 cylinders and the pull start. I think mabey he has unplugged the speedo or something but from my looks I dont see anything, I am not familiar with the wireing of the sled yet and was wondering where all the wires should run to. If it helps any there was a DC Silencer put on it that adds 10 hp and loses like 4 pounds. Thanks in advance.