Buell S1 Lightning Workshop Manual page 252

GENERAL
See Figure 6-9. The purpose of the clutch is to smoothly dis-
engage and engage the engine from the rear wheel for start-
ing, stopping and shifting gears.
The clutch is a wet, multiple-disc clutch with six steel plates
(19), one spring plate (20), and eight fiber (friction) plates (18)
stacked alternately in the clutch shell (26). The order of plate
assembly, from inboard to outboard, is as follows:
F - St - F - St - F - St - F - Sp - F - St - F - St - F - St - F
(F = Friction plate, St = Steel plate, Sp = Spring plate)
The friction plates (clutch driving plates) are keyed to the
clutch shell (26), which is driven by the engine through the
primary chain. The steel plates (clutch driven plates) and the
centrally located spring plate (also a clutch driven plate) are
keyed to the clutch hub (23), which drives the rear wheel
through the transmission and secondary drive belt.
SYMPTOM CAUSE (CHECK IN FOLLOWING ORDER)
Clutch slips. Incorrect clutch release adjustment.
Worn clutch plates.
Clutch drags. Incorrect clutch release adjustment.
Worn clutch release ramps or balls.
Warped clutch steel plates.
Blade worn or damaged clutch gear splines.
Overfilled primary.
6-8
CLUTCH
When the clutch is engaged (clutch lever released), the dia-
phragm spring (11) applies strong inward force against the
pressure plate (17); the pressure plate then presses the
clutch plates (18, 19 and 20) together, allowing no slippage
between the plates and causing the plates to turn as a single
unit. The result is that the rotational force of the clutch shell
(26) is fully transmitted through the "locked" clutch plates to
the clutch hub (23). As long as the transmission is set in a for-
ward gear, power from the engine will be transmitted to the
rear wheel.
When the clutch is disengaged (clutch lever pulled to left han-
dlebar grip), the pressure plate (17) is pulled outward (by
clutch cable action) against the diaphragm spring (11),
thereby compressing the diaphragm spring. With the pressure
plate retracted, strong inward force no longer squeezes the
clutch plates (18, 19 and 20) together. The friction plates (18)
are now free to rotate at a different relative speed than that of
the steel and spring plates (19, 20) (i.e. – slippage between
the clutch plates occurs). The result is that the rotational force
of the clutch shell (26) is no longer fully transmitted through
the "unlocked" clutch plates to the clutch hub (23). The engine
is free to rotate at a different speed than the rear wheel.
Table 6-1. Clutch Troubleshooting
REMEDY
Check and adjust clutch release mechanism.
Check service wear limits. Replace plates.
Check and adjust clutch release mechanism.
Replace release ramps and/or balls.
Replace clutch steel plates.
Replace clutch gear or hub as required.
Drain lubricant to correct level.