Modern "B" Main Seal
A modern cork/neoprene style seal to keep the oil in the motor instead of on the drive way! The crankshaft must be machined to use this style of seal. The slinger on the crankshaft has to be machined down to 2.340"/2.350" in order to use this seal. See downloadable instructions for specifications on what needs to be machined on the crankshaft. U.S.A.