i have a 01 600 xc. the funny thing this sled has never acted up, but after a 100 miles on it i cant rev over 4k all it does is back fire studder and so on. i have cleaned my carbs, took the sensor off, power values are clean, discountec almost every conection and changed fuel. i have know i deal what the heck is up. starts fine, idels like a polaris and then nothing no power to get it up on a trailer. any help would be great.