Fuel Mixture Screw

The more you turn out the mixture screw, does it richen or lean out the fuel? I jetted my 650L & it runs excellent, but the tip of the plug is a light grey.

Thanks

The more you turn out the mixture screw, does it richen or lean out the fuel? I jetted my 650L & it runs excellent, but the tip of the plug is a light grey.

Thanks

The "mixture screw" is really the pilot screw. It fine tunes the pilot circuit fuel mixture at idle to about 1/8 throttle. Backing it out counter clockwise richens it up. Turning it in clockwise leans it out.

Lighter plug colors could mean the either the pilot circuit or the main fuel mixtures are lean. Darker colors mean the mixtures could be a bit rich. Tan or Brown is understood to be the ideal color when doing plug chops & color checks.

Thanks

Generally speaking if the screw is between the head and carb its for fuel. Out is richer. between the carb and airbox its air, so out is leaner.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now