Royal Enfield 500 TWIN 1949 Workshop Maintenance Manual page 15

ROYAL ENFIELD WORKSHOP MANUAL
On earlier "500 Twin" models no provision
was made for adjusting the dynamo chain, but a
slipper can now be provided, if necessary.
8. Removal of Dual Seat
Remove the nuts from the two fixing bolts
securing the seat which can then be unhooked at
the front and lifted off.
9. Removal of Petrol Tank
Turn off the petrol tap.
Disconnect the petrol pipe.
Remove the two bolts which secure the tank
to the frame at front and rear and it can then be
lifted clear.
10. Removal of Cylinder Head
First remove the petrol tank and petrol pipe.
(Subsection 9.)
The dual seat may also be removed if
desired. (Subsection 8.) Remove the head steady
bolt and bracket or the head steady.
Disconnect the oil pipes and plug leads.
_ Remove the exhaust pipes and carburettor and
induction pipe.
Turn the engine until both valves are closed.
Remove the five cylinder head nuts and lift off
the head.
Section C1 Page 4
In replacing the head, see that the push rods
are the right way up (shallow cups upwards). If
steel push rods are fitted, the wide cup should be
upwards.
Apply a thin coat of jointing compound to
both sides of the gasket and place it in position.
Lower the cylinder head over the push rods,
making sure that the rockers locate in the push
rod cups.
Fit the head nuts and washers and partially
tighten down.
When both heads have reached this stage, fit
the induction pipe and tighten the nuts. The
cylinder head nuts can now be finally tightened
down progressively and diagonally from one
side to the other to prevent distortion. After the
engine has been run long enough to get
thoroughly hot, the tightness of the nuts should
be re-checked.
11. Removal of Valves
Remove the rocker box covers, each held by
four nuts, swing the rocker clear of the valve and
lift or prise away the hardened steel thimble or
end cap. If this has stuck, it can be removed by
means of a screwdriver. Using a suitable valve
spring compressor, compress the valve springs
and remove the split conical collets from the end
of the valve stem. Slacken back the compressing
tool and release the springs. Withdraw the valve
and place its springs, top spring collar (and
bottom collar if it is loose) and split conical
collets together in order that they may be
re-assembled with the valve from which they
were removed.
Deal similarly with the other valves in the
heads.
If the valve will not slide easily through the
valve guide, remove any slight burrs on the end
of the valve stem with a carborundum stone. If
the burrs are not removed and the valve is forced
out, the guide may be damaged.
12. Removal of Rockers.
Turn the engine so that the valve is closed.