I decided to change my jet from a 130 to 120 because of the heat and and low altitutudes I ride. When I put in the 120 I have to take my airbox cover off or it just bogs with anything more than 1/4 throttle. With the cover off it runs great. This seems backwards to me..Would appreciate any help. The bike is stock except a uni air filter.....Thanks

 

Sounds like your running lean ,if you put a uni filter on you shouldnt have to down jet, you already leaned it out by letting more air in through the filter. Put the stock jet back in and see how it runs. The more air you let in through the air box the more fuel you need.

 

i agree w/ vig. pull your plug out and look at it and it will tell you if its running too lean/rich. i think there jetted for like 40 degree to like 80 degrees or something like that. just a guess though.

 

Thanks guys. My manual says that for my alitude and temp I need a 120 jet. I have had the bike for years and added the filter last year it had been running good. I guess I should have listened to the old saying "If it ain'rt broke don't fix it"... I was looking for a little more summer power. The only thing that puzzles me is if the new jet is letting in less fuel why do I have to take the cover off the air box to get it more air so it won't bog down???? What am I missing??