I think the guy who put the motor in it, (the last owner) used the 600 xcr carbs, I ran it last year and it had 340, 35s in it. It looks like it ran lean. the pistons are messed up on the exhaust port side, also a wrist pin came out or he forgot to put it in which messed up one jug, The wash seemed ok on two cylinders but the middle where the wrist pin came out it was blackend completely. The stock jetting was 680 50. Was wondering if running that low of jetting on a sled that calls for 680's may had something to do with it..... Also I was just in the garage taring it apart some more, Putting a new seat on it and just going over everthing, I checked the gearing and its set up 21/35.. What kind of set up is that? From what I've gathered from browseing this site, 20/39 is the perfered set up. Do U think that had something to do with it too? I'll go check those sites out too, thanks.