Hey all. I'm up here at the lake and the weather has turned a lot warmer. New sled is running real rich, not so much pull as when it was colder. 07 HO IQ running stock 420 jets. I could waste a day and get new jets but was wondering what the effect would be by moving the neddle jet clip one position down. One jet size smaller, more ?Any body in the know or is this not a good way to lean it out a bit.

If u move the needle one clip position down(leaner),it's about a half a jet size.So if ur running 420 mains it would be a 410 & 1/2.

if you move the clip down this will raise the needle, thus richening it. you want to go the other way. about the whole 410 1/2 jet thing dont know so much. it will lean out your jetting from 1/4 to 3/4 throttle. main jet size will stay the same.

Ditto that.
Spend the $200 or so on a Tempaflow system and don't worry about weather related performance and mileage again! I'm surprised not many people talk about it much. Skidoo uses a similar system on 800's.

Also, can turn the fuel screw in to clean up the idle, & just off idle area. Not sure if the carbs have them, but if they have an air screw you can turn it out a little to clean it up in the 1/4 - 1/3 throttle range after you have dropped the needles.