40 / CYCLE WORLD
The spinning engine is turning the
clutch outer drum and the five or
more friction discs it drives. The in-
ner clutch drum and the steel plates
to which it is splined remain station-
ary because the act of putting the
transmission into gear connects gear-
box input and output shafts to each
other. Because the bike is at rest, the
rear wheel and everything connected
to it—drive chain, plus both gearbox
shafts—remain stationary.
To depart, you smoothly advance
the throttle while with your left hand
feeling for the “engagement point” —
the lever position at which significant
friction begins to occur between the
friction discs (spinning with the en-
gine and clutch outer drum) and the
steel discs (splined to the clutch inner
drum and connected to the station-
ary gearbox input shaft).
“Motorcycle
clutches have
worked this way
for a century,
with variations.”
RIGHT:Here is the Suter clutch in pieces.
At bottom, the outer hub with integral
drive gear. Next is the ramp unit with five
balls, each in its own ramp. Above are the
inner hub, diaphragm spring, the plate
stack (frictions and steels) and at top, the
pressure plate that bears against them.