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.
