Harley Davidson (1970 to 1978) Sportster XL/XLH/XLCH/XLT-1000. Service manual — page 6

OILING SYSTEM (1977 AND LATER) (Figure 3-3)

1. Oil is supplied to the gerotor type oil pump by gravity feed from the oil tank. Oil enters the feed section and fills a cavity located under the feed pump.

NOTE

A complete explanation of the gerotor pump is given in "GEARCASE" section. See "OIL PUMP - 1977 AND LATER.”
2. The feed pump transfers oil from the inlet cavity to the check valve located in the outlet line.

3. The one way check valve is preset to open at 4-6 psi oil pressure. This valve prevents gravity oil drainage from tank to engine and acts as a restriction to activate pressure switch.

4. When adequate pressure is produced, the oil pressure indicator light sending unit is activated and the check valve opens.

5. With the check valve open, oil flows into the right crankcase through a hole located in the oil pump gasket surface. Oil enters gearcase cover passage through hole in gearcase cover gasket

6. Oil flow is then routed to both the crank shaft and the cylinder head areas. Oil enters a hole in the end of the pinion gear shaft and travels to the right flywheel where it is routed through the flywheel to the crank pin. Oil is forced out of the crank pin through three holes located to properly lubricate the rod bearing assembly.

f. Oil which does not enter the pinion gear shaft travels upward through the gearcase cover to the right crankcase. Oil flow continues through a channel in the crankcase to the overhead oil lines to both front and rear intake rocker arm shafts. The oil provides lubrication to the rocker arm shafts, bushings, intake valves and pushrods

8. Oil flow continues around a groove machined in the outside diameter of the large end of the rocker arm shaft and through the rocker arm cover to the exhaust rocker arm shaft. The exhaust rocker arm bushings, valves and pushrods are lubricated in the same manner as described for the intake shafts.

9. Oil collected in the pushrod area of the cylinder heads flows down the pushrod covers to lubricate the tappets. Tappet rollers are lubricated by oil draining into gearcase through two drain holes in tappet.

10. Oil collected in the intake and exhaust valve spring pockets drains to the flywheel compartment through holes drilled in each cylinder Oil returning from the heads, rod assembly and gearcase collects in the sump area below the flywheels.

11. Oil collected in the sump area returns to the scavenge section of the oil pump through a passage located in the rear section of the sump. Oil flow to the pump is accomplished by the scavenging effect of the pump and by 4ie pressure created by the downward stroke of the stons.