Model Engine Company of America

Rear Rotary valves work the same as the crank window. You can usually have the option of running in either direction by simply changing the location of the crankpin. Be sure you have the boss for mounting the carburetor in the proper position.

Shown here is the typical upright and upside down position. Upright position will perform better.

You can also mount the rear cover 90° off to run the engine in reverse, clockwise. The performance of the inverted position may not be as good as the upright position.

Which Position for the Rear Disc Valve
The following should be self explanatory... Remember this is looking from crankshaft side of engine.

This is the normal position for a carburetor, on the upper location of the cover.

To run the engine in reverse the cover must be rotated 90 degrees. The screw bosses will not usually align nicely but the screws will fit.

If you prefer, for whatever reason, the rear rotor cover may be installed upside down. Be sure to read the warning below.

Inverted position means the carburetor is on the lower part the cover, not the normal position.

You can run the back covers in either direction BUT be sure the piston skirt clears the cover. Please read ...
This basic information also applies to the rear rotor cover.


The above information is provided as a guide. Since MECOA/K&B has no way of determining
the ability of the individual using and understanding this information, we assume absolutely
NO RESPONSIBILITY for any damage to person or property from the use of this information.

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