Motorcycle Repair: Idle Adjustment, air fuel mixture, yamaha yz490

Question
Mark,
    Hi, I have a 1983 Yamaha YZ490. The bike runs great but will not idle which gets to be a pain in the ass when im in tight spots. I turned the idle srew in to get the right idle but then it was hesitating when I would get on it. I found out the Air screw had to be adjusted as well. If im turning in on the idle screw which way do I turn the Air screw?.
                                  Thanks,
                                   John

Answer
Hi John,

Air screws are turned "IN" (less air) to richen, and "OUT" (more air) to lean the air-fuel mixture.

I suspect the pilot circuit may be obstructed by varnishing or other contamination of the fuel and causing the idle problem.

Respectfully,
Mark Shively