Idle mixture screws

[Jeff]

On a 1983 R 100, when I set the idle mixture screws for best idle I have 1 set at 1 turn open and the other at 1 1/2 turns open. valves and timing are good and bike runs fine otherwise. Do I have a problem or has someone in the past run the screws in too far and damaged the seats for the screws? May be another good cleaning?

[TZOLK]

I have the same deal on mine. My left starts to bog at 1/2 turns out where my right starts to bog at 3/4 turns out. Ive discovered when going through the carbs that the left idle circuit had fine grit at the nose of the needle and probably wore the orifice out making it run more rich per given turn. So they are now just adjusted at what position they run best at regardless of symetry. The given turns in the book is just ballpark anyways. I have mine set to where they start to idle the highest then moved one notch to the lean. Doesnt seem to cut out coming down from speed as they used to.

[PGlaves]

There are several posssibilities - which still add up to probably nothing. At closed throttle very little intake air is moving. So very slight differences can appear to be large. Something as simple as a few valve stem deposits on one intake valve more than the other can account for this. But, the adjustment difference is also often a sign of an intake air leak. In this case it wouldn't be a very big one. Throttle shaft O ring or carb spigot rubber tube are the two most common. I'd check for a leak - but then I'd just ride it.