One-Way Clutch System (Type C: Inner Push Type With Back Torque Limiter Mechanism) - Honda Motorcycle Service Manual

CLUTCH
ONE-WAY CLUTCH SYSTEM
(TYPE C: INNER PUSH TYPE WITH BACK TORQUE LIMITER MECHANISM1
On rapid downshifting from high RPM, the compression braking forces created by the engine can exceed the rear wheel's
traction; the engine becomes a rear wheel brake. This can cause momentary lockup of the rear wheel
-
until the compression
braking force drops below the level necessary to make the rear tire break traction. If multiple downshifts are made, the result
will be a much longer loss of traction. The one-way clutch system has been specifically designed to prevent this loss of
traction.
CLUTCH HUB, INNER
ONE-WAY SPRAG
CLUTCH
CLUTCH HUB, OUTER
(no splines but receives
power via the one-way
sprag clutch)
NER PORTION
(Always locked during
deceleration.)
deceleration.)
The major difference between this system and a conventional
clutch is a two-piece clutch hub, inner and outer. In addition,
the outer portion of the clutch hub, that which controls the
majority of the clutch plates and discs, is driven by a special
one-way sprag clutch.
The inner portion of the clutch hub is splined to the transmis-
sion's mainshaft as is normal. But
it
only controls about two-
fifths of the clutch plates and discs. This portion of the clutch
transmits power and deceleration forces in the usual manner.
The outer portion of the clutch hub is not splined to the
transmission's mainshaft. It controls about three-fifths of the
clutch plates and discs. This portion transmits power when the
sprag clutch is locked up, such as during normal acceleration,
cruising, and deceleration. But it will slip during high RPM
deceleration.
OPERATION:
When the transmission is downshifted from high RPM, it
causes a backloading at the clutch because of the forces
generated by the engine's compression braking effect. If these
forces approach that which will cause the rear wheel to lock
up, the one-way clutch will disengage the outer portion and
allow the inner portion to slip.
It
will do this to a degree that
allows the rear wheel to maintain traction while maintaining
the highest effect of engine braking. So rather than being a
harsh ON or OFF mechanism, the one-way clutch determines
the correct amount of slip for each situation, all the while
maintaining maximum possible engine braking effect.
SPRAG CLUTCH CLUTCH HUB,
Date of Issue: Sep., 1988
O HONDA MOTOR CO., LTD.