General

The oil feed pump and scavenger (oil return) pump are gear type pumps housed on one pump body and located on rear of gearcase on right side of motorcycle. The feed pump incorporates an automatic bypass valve that reroutes surplus oil (above the amount needed to lubricate the engine) directly to the gearcase or oil tank. A ball check valve is located ahead of the pressure regulating valve to prevent oil drainage from tank, and to operate the pressure switch.

Under normal operating conditions, the pump is a comparatively trouble free unit. The most common trouble with pump operation is the introduction into the pump of a metal or hard carbon chip. If either gets between the gear teeth, it is possible to shear a key, fracture a gear or break off a gear tooth.

If oil fails to return to the tank, check the scavenger pump gear drive shaft key. When the engine receives no lubrication (oil remains in tank), the drive shaft key on the feed pump drive gear may be sheared. Both conditions together could be caused by shearing of the oil pump (gearcase) drive gear key. In cold weather slush ice formed from moisture condensation in oil may block oil passages and cause any of above troubles.

DISASSEMBLING (Figure 3-24)

The oil pump may be removed from the motorcycle as a unit after gearcase cover is removed. The oil pump may be disassembled, piece-by-piece without removing gearcase cover, with engine in chassis as follows:

Disconnect oil lines and oil pressure switch (1) from pump. Remove bolts and lockwashers (2)from gearcase studs, that hold oil pump cover in place. Remove oil pump cover (3) and gasket (4). Remove lock ring (5), drive gear (6), gear key (7) and idler gear (8). Remove two oil pump body mounting stud nuts (9) and slip pump body (10) off studs and gear drive shaft (11). Remove drive gear (12), key (13), and idler gear (14).

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