I noticed a very slight popping when I back off the throttle at low speeds. Everything else seems to be dialed in perfect. The plug looks great. I just wondered if I should go to the third position on the clip or stay at the second? Does a little lean on the mid-range affect anything. Only if I ride real slow for 5 minutes of so does the fan come on.

Specs: UNI in box lid on. Second clip. Dyno Jet needle and 185 main. 500' altitude. Trail riding mainly. No drag racing in NW PA.

 

I would wanna be alittle rich rather then lean. If i was you i was try the third notch. Also you could try turning your air mixture screw out a half a turn. Where is it at right now?

 

its safer to be a little rich then a little lean. engine can get up and cause pre mature wear. i'm having the same problem with my KFX right now. i got a white bros pipe and they suggested a 165 with the lid off but i wanted the lid on so i'm only running a 138 and its a little lean. if my dealer has the jets in tomarrow i'm going to go to a 140 or 142. I would richen your mixture if i was you. Its always better to be a little rich as opposed to a little lean.

 

Running lean causes the engine temps to increase. Running a tad rich keeps the temperature down a bit and is safer for the long haul (so long as your not fouling plugs and blowing lots of black smoke out the back), especially on an air cooled engine. A recipe for disaster is to have a bike leaned out idling for a long time on a hot day.