Royal Enfield 350 BULLET 1949, Workshop Maintenance Manual

Page: 14 / 102

ROYAL ENFIELD WORKSHOP MANUAL
SECTION C2
Service Operations with Engine in Frame
350 Bullet 1949 - 1955
500 Bullet 1953 - 1955
1. Removal of the Timing Cover
First place a tray under the engine to catch
the oil which will escape when the cover is
removed.
Remove the exhaust pipe and silencer.
Remove nine screws from the cover, taking
care not to lose the sealing washers, one for each
screw.
Draw off the timing cover, tapping it lightly if
necessary.
In refitting the timing cover see that the joint
washer is correctly located over the oil holes,
using a little grease (not compound) to hold it in
position.
See that the cork plug is in position in the
hole in the pump worm. If the plug is damaged it
should be renewed to ensure oil pressure to the
big end bearing.
When refitting the timing cover it is important
that the engine is turned gently forwards while
the cover is being put in place. This will help the
engagement of the pump worm with the pump
spindle and prevent damage to the gears.
The filter chamber should be filled with
clean oil before the timing cover is refitted.
To verify that the oil pumps are working after
replacing the timing cover, start the engine up
and remove the oil filler cap so that the return of
oil through the relief valve can be seen. It may
take several minutes before there is sufficient oil
in the engine for the return flow through the
relief valve to commence.
2. Valve Timing
The cams are integral with the cam pinions
and the position for correct timing is marked on
the pinions by small dots.
Rotate the engine to top dead centre and put
the exhaust (or right-hand) cam pinion in
position so that the pair of dots on it are opposite
the pair of dots on the timing pinion on the
crankshaft.
Put the inlet (or left-hand) cam pinion in
position so that the single dot on it is opposite
the single dot on the exhaust cam pinion.
The correct timing at .012 in. tappet
clearance is as follows
"350 Bullet"
Exhaust opens 75° before bottom dead centre.
Exhaust closes 35° after top dead centre.
Inlet opens 30° before top dead centre.
Inlet closes 60° after bottom dead centre.
"500 Bullet"
Exhaust opens 75° before bottom dead centre.
Exhaust closes 35° after top dead centre.
Inlet opens 40° before top dead centre.
Inlet closes 70° after bottom dead centre.
3. Tappet Adjustment
The tappets are adjusted by the ball and
socket joints which are located in a compartment
at the side of the cylinder and access to which is
obtained by removing the inspection cover.
Before checking the clearance or making any
adjustment, rotate the engine until the piston is
at the top of the firing stroke. This will ensure
that both valves are closed and that the tappets
are well clear of the silencing ramps on the
cams. If the cylinder head has been dismantled,
make sure that the end caps have been put back
on the valve stems.
Because of the ball and socket joints at the
bottom of the push rods, the tappet clearance
cannot be measured there, but between the valve
Section C2 Page 1
www.hitchcocksmotorcycles.com