Which Idle mixture setting for baseline?

[Forden]

I've seen two recommendations for baseline setting of mixture screws after rebuild-- 1 1/4, and 2 1/2, possibly (?) depending on if you have the early or later BS34's. I have the earlier version, according to DiverRay's Carb ID Guide.

Which is correct for me? I'm going back to square one with everything to try to eliminate my racing idle problem.

Thanks all.
Mike

[oldyam80sg]

I always thought or read it was 2 turns out after lightly seated. When you turn them in dont crank on them or you will break the tips. On my Kawasaki you have a rubber o-ring and a washer to also contend with. I just had to replace 2 rubber o-rings as they were a bit worn.

[DiverRay]

I usually start at 1 1/2 out from a SOFT seat on the older carbs.I also tune by ear, but then I've been doing carbs for about 55 years.... You want to go out or in about 1/8 turn, blip throttle, and see if the RPM has gone up or down. The other way is with a vacuum gauge set on the carbs. Turn one way or the other for the greatest vacuum. Do carbs one through four, then go again to make sure they are all as best as you can get. Don't forget a good fan blowing across the engine to keep things from over-heating!

[bikerphil]

Everyone seems to do it differently. I start at 3 turns out (early or late type carbs), and with my gauges hooked up, adjust while synchronizing to achieve the highest vacuum reading.

Edit: If your gauges are Morgan Carbtune, they may not be sensitive enough. You need standard dial type gauges to do this, unless you adjust by ear as Ray suggested.