Royal Enfield CONSTELLATION 1958, Workshop Maintenance Manual

Page: 48 / 106

Section E7 Page 1
SECTION E7
Gearbox and Clutch
1958 – 1960 Constellation
1. Description of the Clutch
The clutch is built into the clutch sprocket
and is mounted on the gearbox mainshaft which
projects through into the primary chaincase.
There are five driven plates which are plain
and four driving plates, giving eight friction
surfaces.
The driven plates comprise the clutch centre
backplate, three plain plates on splines on the
clutch centre and the clutch cover plate.
The driving plates comprise the clutch
sprocket itself, which has a ring of friction
material riveted to each side, and three plates
which rotate with it. Early models have all three
plates pierced and fitted with Klingerite inserts,
but later models use a pierced plate with friction
material inserts only on the plate nearest the
clutch sprocket. The other two plates employ a
material particularly resistant to slip, which is
bonded on to both sides of each plate.
The clutch plates are held in contact, when
driving, by six coil springs and are released
when the springs are compressed by the clutch
operating mechanism.
The clutch operating mechanism consists of a
torque arm which is held stationary by a stud in
the chaincase and an operating lever on the same
centre is rotated relatively to the torque arm, with
a scissor-like movement, by the clutch cable
connected to the clutch lever on the handlebar.
Between the operating lever and the torque arm
are four 1/4 in. diameter steel balls in recesses so
that, when the levers are rotated relatively to
each other, the balls are forced out of the
recesses forcing the levers apart and thus
compressing the clutch springs.
2. Description of the Gearbox
The operation of the gearbox is shown
diagrammatically in Fig. 3.
The clutch sprocket A is mounted on the end
of the mainshaft B which passes through the
mainshaft sleeve C on the end of which is the
final drive sprocket D.
At the other end of the mainshaft B is a
pinion E which engages with a pinion F on the
layshaft G. At the other end of the layshaft G is a
pinion H engaging with a pinion J which runs
free on the mainshaft sleeve C.
The mainshaft sleeve C has splines on which
slides a double pinion KL. This double pinion
KL engages with two pinions M and N which
are free to rotate or slide on the layshaft G.
The double pinion KL has dogs at each end
which can engage with dogs on the pinion E or
on the pinion J.
The pinions M and N have internal dogs
which can engage or slide over projecting dogs
P and Q on the layshaft G.
The double pinion KL and the pinions M and
N all slide together and are moved by the
operator fork R and are located by a spring
plunger S which engages with a notched plate
which is part of the operator arm R.
The kickstart lever is connected to the pinion
F on the layshaft by a ratchet mechanism which
automatically disengages when the lever is
released.
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