TB Stroker Crankshaft, 51mm 6v – Various 3 & 4 Speed Models Bike Protection The BBR springs are are

The BBR springs are are stiffer

1/2" Longer than stock

Gradual continuous hammering technique allows spoke to bear more oscillating loads

Add the high compression 52mm bore kit with the 51mm stroker crank that brings up the bore to 108cc and makes for a strong power band

TB Stroker Crankshaft, 51mm 6v – Various 3 & 4 Speed Models Bike Protection The BBR springs are areTB Stroker Crankshaft, 51mm 6v Various 3 & 4 Speed Models Replacement TB 51mm Stroker Crankshaft 6v Type with long rod for 3 and 4 speed models. Note: Only for use with 4 speed CT70H, SL70, and XL70. Also for 81 & up ATC70 and 3 speed 80 81 CT70 Must use compatible TB Parts piston.