Carburetor Adjustment

A carburetor which is out of adjustment will adversely affect the performance of the engine, therefore it is important that the carburetor always be maintained in perfect adjustment.



Carburetor adjustment should only be made when the engine is at operating temperature.

  1. Adjust the stop screw (1) so that the exhaust pressure is the same for both the right and left side. If the engine speed does not decrease when the stop screw is screwed out, loosen the lock nut (5) and screw in the cable adjuster (4) about one turn. The engine rpm at this point is 1,200 rpm.
  2. Starting with either the right or left carburetor, manipulate the pilot screw (3) and find the point of highest rpm; the same should be done with the opposite carburetor. Turning the pilot screw in will give a lean fuel air mixture, turning the screw out will give a rich mixture. The pilot screw (3) should be set at a point of one turn out from full close.
  3. After completing the adjustment in paragraph 2 above, recheck the exhaust pipe pressure on both the right and left sides and if necessary, readjust the stop screw as was done in paragraph 1.
  4. Repeat the procedure from paragraph 1 through 3 several times so that the pilot screw is set to give the optimum mixture, while the stop screws are set to provide the specified rpm and the same exhaust pressure on both the right and left sides.
  5. Next, make the adjustment so that the right and left throttle valves will both move by the same amount when the throttle grip is moved slightly. This adjustment can be made by placing your hand under the carburetor and noting the movement of the throttle lever, or by observing the movement while the throttle grip is slowly moved and checking to see that the throttle levers start moving at the same time. If adjustment is required, loosen the lock nut (5) and perform the adjustment with the throttle cable adjuster (4).