Engine Notes

ALL PRODUCTION MODELS AS OF 5/1/73 - TENSION BOLT "O" RING CHANGE  - "O" rings on tension bolts have been replaced by a rubber coated washer on all production models as of May 1, 1973. Rubber coated washers are interchangeable with all "O" rings used on earlier models.

ALL PRODUCTION MODELS AS OF 5/1/73 - INNER OIL SEAL SPRING CHANGE  - Inner oil seal spring has been changed on all production models as of May 1, 1973. The new front oil seal spring is identified by a cream color on spring and new rear oil seal spring is identified by a blue color on spring. New design inner springs are interchangeable with springs in earlier models, but additional holes must be drilled in groove in rotor to prevent spring and seal from rotating. A suitable jig (No. 49-0862-190) is required to drill new holes in rotor. A 0.1" (3 mm) diameter drill is used and holes are drilled approximately 0.02" ± 0.004"(0.5mm ± 0.1 mm).

ALL PRODUCTION MODELS AS OF 5/1/73 - OIL COOLER BY-PASS VALVE INSTALLATION  - All production models as of May 1, 1973 (also some earlier models) are equipped with an oil cooler by-pass valve. This valve prevents loss of engine supply oil in cold weather. Oil will flow directly to engine until engine temperature is 185°F. Oil cooler by-pass valve is available to be installed on earlier models not equipped with valve from factory.

ALL PRODUCTION MODELS AS OF 10/1/72 - LARGE ROTOR HOUSING "O" RING CHANGE  - A new large rotor housing "O" ring oil seal of more durable material has been installed on all production models from October 1, 1972. New "O" ring is recognizable by being red in color with a tan liner and has a square cross section. Old style "O" ring is black in color with a round cross section. New seal is to replace old seal in all engines. Install new "O" ring with tan liner toward combustion chamber and bound resin joint placed at upper side of rotor housing.