Royal Enfield CONSTELLATION 1958, Workshop Maintenance Manual

Page: 93 / 106

adjuster cam, preferably marking it to ensure
that it is replaced in the same position. Now
slide the distance collar out of the fork end and
lift away the speedometer drive gearbox, which
can be left attached to the driving cable. The
spacing collar and the felt washer behind it may
now be removed to prevent risk of them falling
out when manipulating the tyre. If, however,
these are too tight a fit in the hub to come out
easily they may be left in place. The main body
of the wheel can now be pulled across to the
right-hand side of the machine, thus disengaging
the six driving pins from the cush drive shell and
enabling the wheel to be removed from the
machine.
When replacing the main portion of the
wheel, reverse the foregoing procedure. The
cush drive shell can be prevented from rotating
when turning the wheel to engage the six driving
pins, if the machine is placed in gear or the rear
brake is operated, taking care, when replacing
the speedometer drive gearbox, that the driving
dogs inside the gearbox engage with the slots in
the end of the hub barrel. Before tightening the
centre spindle make sure that the speedometer
drive gearbox is correctly positioned so that
there is no sharp bend in the driving cable.
3. Removal and Replacement of Complete
Wheel for Access to Brake
Place the machine on the centre stand and
remove the rear mudguard unit. Disconnect the
rear driving chain at the spring link and loop the
top end of the chain over the tag provided at the
top of the fixed portion of the chaincase. Pull on
the other end of the chain and allow it to hang.
Unscrew the rear brake rod adjusting nut
completely and depress the brake pedal so as to
disengage the rod from the trunnion in the brake
operating lever. Unscrew the brake cover plate
anchor nut and remove this together with the
washer behind it. Unscrew the loose section of
the spindle two or three turns and the spindle nut
by a similar amount. Mark the chain adjuster
cams to ensure replacing in the same position.*
Disconnect the speedometer driving cable and
slide the wheel out of the fork ends, tilting it so
as to disengage the end of the brake shoe pivot
pin from the slot in the fork end.
When replacing the wheel make sure that the
dogs on the gear in the speedometer drive
gearbox are engaged with the slots in the end of
the hub barrel.
* Note that the wheel is not necessarily correctly lined
up when the same notch position is used on both adjuster
cams. Once the position of the cams which gives correct
alignment has been found this alignment will, however, be
maintained if both cams are moved the same number of
notches.
Make sure also that the speedometer drive
gearbox is correctly positioned so that there is
no sudden bend in the driving cable. When
replacing the connecting link in the driving
chain, make sure that the closed end of the
spring link points in the direction of travel of the
chain. Replace the chain adjuster cams in their
original positions or, if necessary, turn each of
them the same number of notches to tension the
chain and maintain correct wheel alignment. If
the chain is adjusted, it will be necessary to
reposition the front part of the chaincase. This is
easily done by slackening the two screws
fastening it to the swinging arm chainstay before
re-assembling the chaincase to the brake cover
plate, then re-tightening the screws. Do not
forget to refit the brake rod and adjust the brake
so that the wheel turns freely when the brake is
off, while at the same time only a small travel of
the brake pedal is necessary to put the brake on.
4. Removal of Brake Shoes for Replacement.
Remove the complete wheel as described
above, then remove the spindle nut, chain
adjuster and the distance collar, thus permitting
the complete brake cover plate assembly, with
operating cam, pivot pin, shoes and return
springs, to be lifted off the hub spindle. The
brake shoes can then be removed after detaching
the return springs. Brake linings for alloy shoes,
are supplied either in pairs ready drilled
complete with rivets (Part No. 4246913X) or
ready fitted to service replacement brake shoes
(Part No. 41342SR). When riveting linings to
shoes, secure the two centre rivets first so as to
ensure that the lining lies flat against the shoe.
Standard linings are Ferodo MS3, which are
drilled to receive cheese headed rivets.
5. Removal of Brake Operating Cam
To remove the operating cam unscrew the nut
which secures the operating lever to the splines
on the cam. A sharp tap on the end of the cam
spindle will now free the lever, after which the
cam can be withdrawn from its housing.
Do not try to remove the brake shoe pivot pin
and nut, as these are brazed to the cover plate.
6. Cush Drive
The sprocket brake drum is free to rotate on
the hub barrel. Three radial vanes are formed on
the back of the brake drum and three similar
vanes are formed on the cush drive shell. Six
rubber blocks are fitted between the vanes on the
brake drum and those on the cush drive shell,
thus permitting only a small amount of angular
movement of the sprocket/brake drum relative
Section L9 Page 2
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