Re: ROTARY VALVE MOTORS??? What is it?

[Leon]

Rotary valves were most common in motors before 1936. As a mater of fact, the carbs on the old Sportsmans, Scouts and Mates were more or less the beginning of the "reed valve" concept, with the exception that the valve was in the carburetor itself an not in the manifold.
The rotary was a cut out in the crank that allowed air to be inhaled into the motor during the compression stroke As the piston nears TDC , the valve closes. On the power stroke, the rotary is still closed, therefore the fuel/air vapor is forced into the combustion chamber as the piston goes toward BDC
Any accessive internal wear, will effect the function of the rotary valves, unfortunately.