Royal Enfield 500 TWIN 1949 Workshop Maintenance Manual page 19

ROYAL ENFIELD WORKSHOP MANUAL
remove the sprocket, undo the nut and use a
Magdyno sprocket extractor-Special Tool No.
14835.
Dynamo. In the case of engines fitted with
coil ignition the sprocket can be withdrawn by
means of a dynamo sprocket extractor-Special
Tool No. E.5127.
26. Removal of Engine and Clutch Sprockets
The primary chain is endless so that it is
necessary to remove both the engine and clutch
sprocket simultaneously.
Unscrew the engine sprocket nut using
Special Tool No. 4877. The engine sprocket is
mounted on splines and can then be removed
with the clutch sprocket.
To remove the clutch sprocket unscrew the
three clutch spring pins and lift away the spring
cap, springs, distance pieces, clutch front plate,
centre retaining ring and the assembly of driving
and driven clutch plates. The clutch sprocket
can then be withdrawn from the centre after
removal of the large circlip which secures it.
When replacing the engine sprocket, take
care that the felt washer is not nipped behind the
sprocket. This would make the engine very stiff
to turn over and would damage the washer and
allow leakage from the crankcase.
27. Removal of Tappets and Guides
It is only necessary to remove the tappets
and guides if they have become worn.
Remove the cylinder heads and barrels.
(Subsections 10 and 15.)
Extract the tappet guides using Special Tool
No. E.5790.
The guides are made from Nickel Chrome
Alloy iron and if a guide should break while
removing it, it can be withdrawn with a pair of
pliers if the crankcase is heated locally with a
blowlamp. Otherwise
dismantle the crankcase and drive the tappet and
guide out from underneath using a heavy bar in
the cam tunnel.
The guide should have an interference of
.0015 to .0025 ins. in the crankcase and can be
driven in with a bronze drift, care being taken
when the guide is nearly home to avoid
breaking the collar.
If a tappet guide is taken out it should be
replaced by an oversize one.
28. Dismantling the Breather
If the breather is not operating efficiently, it
may cause pressure in the crankcase, instead of
a partial vacuum, giving rise to smoking or
over-oiling. See that the discs and backplate are
clean and undamaged and that the discs are
seating properly.
Section C1 Page 8
it is necessary to
When re-assembling the breather, apply
jointing compound sparingly to the back of the
steel plate taking great care to keep it away
from the discs or their seatings.
On earlier models fibre discs were used in
the breather, without a backplate. If the fibre
discs are re-placed by steel discs, the steel
backplate must be fitted to prevent wear on the
surface of the alloy casting.
On very early models of the "500 Twin" the
breather was located in the end of the crankshaft
with a cork seal to prevent breathing into the
chaincase.
29. Removal of Clutch
Remove the engine sprocket and clutch
sprocket together as described in Subsection 26.
To remove the clutch hub, hold the clutch
with Special Tool No. E.4871 and remove the
centre retaining nut and washer with a box
spanner.
The hub can then be withdrawn from the
shaft with Special Tool No. E.5414.
30. Removal of Final Drive Sprocket
Remove the clutch
Subsection 29.
Remove the primary chain tensioner.
Remove the rear half of the primary chain
case by taking out three socket screws.
Remove the grub screw locking the final
drive sprocket nut.
Hold the sprocket and remove the nut (Right
Hand Thread). The sprocket can then be with-
drawn.
31. Removal of Bearing Housing Felt Washer
Remove the engine sprocket, clutch and rear
half of the primary chain case.
The felt washer is located in the steel
housing at the back of the chain case.
Great care must be taken not to nip the felt
washer behind the sprocket on re-assembly as
this would make the engine very stiff to turn
over and would damage the washer and allow
leakage from the crankcase.
32. Oil Pipe Unions
"Meteor." The oil feed to the rocker gear is
through pipes from unions at the back of the
crankcase below the cylinder base to unions on
the cylinder heads. The unions in the crankcase
are fitted with steel wire thread inserts to
prevent the threads in the aluminium from
stripping.
Those in the cylinder heads are not provided
with thread inserts because they are not so liable
as described in