This is happening during idle, and somtimes it kills the engine. Would appreciate anyone that can tell me what is going on ASAP as I am leaving today for a 3 day quad trip in the mountains of Jellico, TN.

Please Please............[img]i/expressions/face-icon-small-shocked.gif[/img]

 

Possible vacuum leak.

Possible binding of the carb spring. Take the airbox lid off and remove the filter and see if the slide is vibrating at idle. It should be completely still.

Give it a little throttle and watch the slides and see if they are opening together and not out of synch.

Try tightening up the pilot screws all the way in and then back each out 3 full turns.

If you're seeing any black smoke at idle or light throttle, the choke could be sticking.

 

Brewster.
I had this problem also.After ruling out jetting problems I found out that the rubber intake boots where they connected to air box were really loose.Thier sort of a pain to get at but once I tightened them the problem went away.

 

Thanks Kevin and IWheelMoses, I will check those items out.

Kevin, when you refer to pilot screws do you mean the air/fuel mixture screws on each carb.....if so I have them set at 2 full turns out at present with 160/165 jetting. What jetting are you currently using? I am in Northern Kentucky, so not at a high elevation.

Brewster

 

Yes, those are your mixture screws. With the Aliens I ended up 3 turns out on the front cylinder and 3 1/2 on the rear. Adjusting those will have no effect on your mains and your mains will have no effect on your idle.
Checking the carb boots was a good idea also.