Adjusting the Keihin Carburetor Idle Mixture
There are a couple of ways to adjust the idle mixture on the Keihin carburetor, using a vacuum meter, or by ear.
Vacuum Meter Method
- Connect a vacuum meter to a port on the intake manifold.
- Turn the idle mixture in or out 1/4 turn until the vacuum needle is steady and you get the maximum idle.
By Ear, or Using a Dwell Meter
- Starting at about 1 1/2 to 2 turns counter clockwise on the idle mixture screws.
- Turn the screw in 1/4 turn. Note: you sometimes need to turn the screw out at first in case it is too far in.
- Wait for the RPM to catch up.
- Turn in 1/4 turn until the RPM starts to drop.
- Turn the screw back out 1/4 turn
