S&S Cycle Crankcases

The functional part of S&S crankcase breather reed valves consists of steel reeds that are normally in the closed position. When the pistons travel downward in the cylinders, pressure in the crankcase below the pistons causes the reeds to open, allowing the air and oil mist in the crankcase to escape into the cam chest. When the pistons change direction and begin traveling back upward in the cylinders, a vacuum is created in the crankcase. The vacuum causes the reeds to close, preventing air from entering the crankcase. The effect is that camchest pressure waves are reduced improving oil return from the heads to the camchest and also a slight vacuum is maintained in the crankcase, improving ring seal.

The functional part of S&S crankcase breather reed valves consists of steel reeds that are normally in the closed position. When the pistons travel downward in the cylinders, pressure in the crankcase below the pistons causes the reeds to open, allowing the air and oil mist in the crankcase to escape into the cam chest. When the pistons change direction and begin traveling back upward in the cylinders, a vacuum is created in the crankcase. The vacuum causes the reeds to close, preventing air from entering the crankcase. The effect is that camchest pressure waves are reduced improving oil return from the heads to the camchest and also a slight vacuum is maintained in the crankcase, improving ring seal.

The S&S Super Stock generator style crankcases are designed with a stock-like original appearance. This gives the engine builder an alternative to attempting costly repairs on fatigued, broken, wornout stock crankcases. In spite of the stock appearance, these cases incorporate updated design features that improve overall engine strength and reliability.

• Pre-clearanced for strokes up to and including 5"
• Motor mounts on crankcases for knucklehead engines are machined to fit stock 1936-‘47 frames.
• An adapter plate is included for 1948 and later style frames ƒƒAll cases are designed for late style generator (two brush type) with 5/16" mounting bolts to eliminate early generator cradle/mounting strap bosses for simplicity and economics
• Use more readily available 1/4"-20 thread fasteners to mount gearcover, oil pump, tappet guides, timer, and timer advance bracket, except KN replacement
• Timken sprocket shaft main bearing, in all years, instead of stock straight roller bearings – resulting in better flywheel assembly stability, placement, and longer engine life

The S&S Super Stock generator style crankcases are designed with a stock-like original appearance. This gives the engine builder an alternative to attempting costly repairs on fatigued, broken, wornout stock crankcases. In spite of the stock appearance, these cases incorporate updated design features that improve overall engine strength and reliability.

• Pre-clearanced for strokes up to and including 5"
• Motor mounts on crankcases for knucklehead engines are machined to fit stock 1936-‘47 frames.
• An adapter plate is included for 1948 and later style frames ƒƒAll cases are designed for late style generator (two brush type) with 5/16" mounting bolts to eliminate early generator cradle/mounting strap bosses for simplicity and economics
• Use more readily available 1/4"-20 thread fasteners to mount gearcover, oil pump, tappet guides, timer, and timer advance bracket, except KN replacement
• Timken sprocket shaft main bearing, in all years, instead of stock straight roller bearings – resulting in better flywheel assembly stability, placement, and longer engine life

The S&S Super Stock generator style crankcases are designed with a stock-like original appearance. This gives the engine builder an alternative to attempting costly repairs on fatigued, broken, wornout stock crankcases. In spite of the stock appearance, these cases incorporate updated design features that improve overall engine strength and reliability.

• Pre-clearanced for strokes up to and including 5"
• Motor mounts on crankcases for knucklehead engines are machined to fit stock 1936-‘47 frames.
• An adapter plate is included for 1948 and later style frames ƒƒAll cases are designed for late style generator (two brush type) with 5/16" mounting bolts to eliminate early generator cradle/mounting strap bosses for simplicity and economics
• Use more readily available 1/4"-20 thread fasteners to mount gearcover, oil pump, tappet guides, timer, and timer advance bracket, except KN replacement
• Timken sprocket shaft main bearing, in all years, instead of stock straight roller bearings – resulting in better flywheel assembly stability, placement, and longer engine life