A crankshaft 12 has a helical drive gear 24 integrally formed as one of the crank webs at one end portion thereof Another crank web 28g outside of the drive gear is made of two parts, an integral balance weight mounting portion 30g and a removable balance weight 31g. The balance weight has a bore that fits over a column and is retained by circumferentially distributed screws 50g. The helical gear reduces gear noise and allows outer diameters (d1, d2 Fig. 5) of the crank webs adjacent the gear to be larger than the tooth bottom diameter (D2) of the gear as tooth grinding is permitted due to the helix angle. The crankshaft may have a second two part balance weight separated from the first.
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