Two-Stroke Lubrication Systems; Separate Oil Systems - Honda Motorcycle Service Manual

LUBRICATION
TWO-STROKE LUBLlCATlON SYSTEMS
Unlike four-stroke engines, two-stroke engines use the internal
crankcase area as a suction chamber and, therefore, cannot
use a sump-type oiling system. Consequently, the following
t w o systems have been adopted i n order to provide lubrication
to the cylinder, piston rings, connecting rod and crankshaft
bearings. Each system type relies on oil ingested together with
the gasoline. In Separate Oil systems, engine lubrication oil is
introduced downstream of the carburetor. Oil is combined
with the gasoline before it reaches the carburetor in Premixed
systems.
SEPARATE OIL SYSTEMS:
Virtually all street motorcycle and scooter two-stroke engines use a pump-operated system t o lubricate engine components.
Oil in this type of system is drawn from a separate oil tank by an oil pump that introduces the oil directly into the airlfuel inlet
tract beyond the carburetor.
Periodic level checks and refilling of the oil tank is required since the oil in the tank is continually drawn upon when the engine
is running.
FUEL TANK
The amount of lubricant delivered t o the engine is dependant
on both engine rpm and throttle position.
INTAKE P ~ P E
Some of these systems include provisions for circulating the
transmission oil within the gearbox portion of the crankcases
with the same oil pump.
THROTTLE CABLE
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OIL CONTROL
Date of Issue: Sep., 1988
O
HONDA MOTOR CO., LTD.