Harley Davidson (1970 to 1978) Sportster XL/XLH/XLCH/XLT-1000. Service manual — page 7

Examine gears (8, 9, 13 and 14) and oil pump breather shaft (19) and idler gear shaft (21) for damage or wear. If the breather valve key (10) is excessively worn and loose on shaft or gear, replace with a new one. Inspect pump ody plate (5) and cover (11). If they are worn or damaged, place them. Examine breather valve (19) and oil pump cover for any wear or damage that might affect its operation. Insert breather valve (19) in oil pump cover (11). Make sure valve turns freely in cover and does not bind.

ASSEMBLING OIL PUMP (Figure 3-25)

Reassembly of the oil pump is essentially the reverse order of disassembly.

Apply a light coating of engine oil to all moving parts before assembling.

Reassemble check valve. See "ASSEMBLING OIL PUMP CHECK VALVE."