I have an 02 stock ZR 800 CCE. It still has the stock jets in it and I was wondering if people are changing them. Cuttin them back a couple sizes. My friend had his Polaris in at the dealer and they said they were jetting down two sizes on most of them. I live in Mi and this is where I primarily ride. It rips but only when it is butt as$ cold out(10° or colder). Which I know that is how it is supposed to be but I want to know if its safe to go down a couple sizes on the main, or even one size. Also. I am new to carbs in Snowmobiles and I don't know what the increments are for jets. I am used to the ones on jetskis and I think they are different. Like one size on a snowmobile is like 10 or something isn't it. EX: Go from a 420 to a 400. Would that be considered two sizes?