Hydraulically Assisted Clutch Summary; Hydraulically Assisted Clutch Construction And Operation; When The Clutch Is Engaged; When The Clutch Is Disengaged - Honda GL1800 Service Manual

TECHNICAL FEATURES
HYDRAULICALLY ASSISTED CLUTCH
SUMMARY
The hydraulically assisted clutch uses engine oil to boost the engagement force against the pressure plate.
This clutch increases the friction force between the clutch plates and discs (pressure force against the pressure plate) with-
out the need for heavy clutch springs. This allows the use of a small and lightweight clutch, which results in a light clutch
lever feel.
High pressure oil is pumped from the oil pump through the crankcase oil passage. Oil flows through the oil passage and is
regulated by the regulator valve. The oil then travels through the oil passage in the clutch cover and joint piece, and goes
to the clutch.
CONSTRUCTION AND OPERATION

When the clutch is engaged:

The pressurized oil flows through the oil passage in the joint
piece and mainshaft, and enters an oil chamber which is
formed by the clutch piston, pressure plate, and clutch center.
Because the clutch piston and clutch center are fixed by the
lock nut via the spring guide, oil pressure moves the pressure
plate towards the clutch center.
The clutch spring is forced against the pressure plate via lifter
plate B. Therefore, the clutch plates and discs are pressed
together by oil pressure and spring force.

When the clutch is disengaged:

The oil outlet ports in the pressure plate are sealed by lifter
plate B. Lifter plate B is pressed against the pressure plate by
the force of the clutch spring. When lifter plate A is pushed
out by the lifter rod via the joint piece and bearing, the spring
force, which acts on the pressure plate via lifter plate B, is
released.
This opens the outlet ports sealed by lifter plate B and oil
pressure in the oil chamber is released. Therefore, oil pres-
sure and spring force are removed, the friction force between
the clutch plates and discs is relieved, and the clutch is
disengaged.
The lifter spring presses lifter plate B against the pressure
plate lightly to prevent the oil in the chamber from leaking.
24-4
IL PASSAGE
REGULAT R VALVE
CLUTCH
CENTER
MAIN
SHAFT
IL CHAMBER
PUSH R D
PRESSURE PLATE
CLUTCH
PIST N
CLUTCH
C VER
J INT
PIECE
SPRING
GUIDE
CLUTCH
SPRING
UTLET P RTS
PRESSURE
PLATE
LIFTER
SPRING
LIFTER
PLATE B
LIFTER
PLATE A
J INT
PIECE