Sifton oil pumps are available for all Harley models for all years after 1935. Flatheads, Knuckleheads, Panheads and Shovelheads manufactured before 1980 may require crankcase modification. Good shop practice for Sifton installation on Harley-Davidson motorcycles manufactured between 1948 and 1962 requires the installer to plug and re-drill the crankshaft feed hole. Installation on models manufactured in the 1970s requires the installer to drill a pressure valve relief hole. Installation of a Sifton oil pump on Panheads manufactured from 1965 to 1969 requires the installer to drill a primary chain oil supply hole.
Fit the pump assembly to the crankcase and inspect to ensure clearance between the oil pump body and crankcase. Improve clearance by carefully grinding down the oil pump body with a grinding tool.
Disassemble, clean and inspect the oil pump. Use combination wrenches to disassemble the oil pump. Reassemble the pump dry without lubrication.
Rotate the pump gears to check for binds. Confirm that drive gear keys are properly installed.
Determine if gears that bind are supply or return gears. Remove and rotate gears that bind 180 degrees.
Apply 20W50 engine oil to the oil pump drive shaft and the drive shaft bushing in the crankcase. Install the oil pump in the crankcase using combination wrenches and a flat head screwdriver. Place the pump drive gear over the drive shaft as the shaft is passed through the bushing and into the crankcase gear compartment.
Install the drive shaft gear key and snap ring with snap ring pliers
Hand tighten the two 1/4-inch x 1 1/2-inch bolts in the upper holes in the oil pump body. Attach the pump cover by hand tightening the four 1/4-inch x 2 3/4-inch bolts.
Turn the oil pump gear to check for binding. Tighten the four 2 3/4-inch bolts in a cross pattern to 10 foot pounds of torque with a torque wrench. Check for binding after tightening each bolt.
Turn the drive shaft to confirm free operation of the pump. Tighten the two remaining bolts to 10 foot pounds of torque with a torque wrench.
Remove the oil pump check valve ball assembly by hand. Pour clean motor oil into the pump supply fitting while turning the oil pump drive gear.
Replace the check ball, spring and cap after oil fills the check valve cavity.
Install the pinion shaft drive gear, pinion gear and remaining parts in the gear case following the procedures stated in the shop manual for your year and model Harley.
Connect the oil lines by tightening hose clamps over the return and supply fittings with a flat head screwdriver.
