Royal Enfield 500 TWIN 1949, Workshop Maintenance Manual

Page: 96 / 110

ROYAL ENFIELD WORKSHOP MANUAL
Section L1 Page 5
12. Reassembly of Brake Shoes, Pivot Pin and
Operating Cam into Cover Plate
No difficulty should be experienced in
carrying out these operations. Make sure that the
pivot pin is really tight in the cover plate and put
a smear of grease in the grooves of the pivot pin
and on the operating face of the cam; also on to
the cylindrical bearing surface of the operating
cam if this has been removed. Fit the operating
lever and trunnion, 23371, on its splines in a
position to suit the extent of wear on the linings
and secure with the nut. The range of adjustment
can be extended by moving the lever on to a
different spline.
13. Centering Cam Housing
Note that the bolt holes in the cam housing,
26347, are slotted, thus enabling the brake shoe
assembly to be centered in the drum. It is not
intended that on rear brakes the cam housing
should be left free to float but the shoes should
be centered by leaving the screws, 26309 and
35140, just short of dead tight. The brake cover
plate assembly with the shoes should then be
fitted over the spindle into the brake drum and
the brake applied as hard as possible by means of
the operating lever. This will centre the shoes in
the drum. The screws should then be tightened
dead tight and secured with the locknuts. If the
shoes are not correctly centered the brake will be
either ineffective or too fierce, depending on
whether the trailing or leading shoe first makes
contact with the drum. With the brake assembly
correctly centered and the screws securing the
cam housing correctly tightened wear on both
linings should be approximately equal.
14. Final Reassembly of Hub before Replacing
Wheel
Before replacing the felt washers which form
the grease seals, pack both bearings with grease.
Recommended greases are Castrolease (Heavy),
Mobilgrease (No. 4), Esso Grease, Energrease
C3 or Shell Retinax A. These are all medium
heavy lime soap or aluminium soap greases. The
use of H.M.P. greases which have a soda soap
base is not recommended as these tend to be
slightly corrosive if any damp finds its way into
the hubs.
Make sure that the inside of the brake drum is
quite free from oil or grease, damp, etc. Replace
the felt washers, distance collars, the brake cover
plate assembly, speedometer drive gearbox,
distance collars, 39315 and 39323, chain adjuster
cams, the loose section of the spindle and the
spindle nut 36651. The wheel is then ready for
reassembly into the machine.
15. Wheel Rim
The wheel rim is type WM2-19 in. plunged
and pierced with forty holes for spoke nipples.
The spoke holes are symmetrical, i.e. the rim
can be assembled to the hub either way round.
The rim diameter after building is 19.062 in.,
the tolerances on the circumference of the rim
shoulders
where the tyre fits being
59.930/59.870 in. The standard steel measuring
tape for checking rims is 5/16 in. wide, .011 in.
thick and its length is 59.964/ 59.904 in.
16. Spokes
The spokes are of the single butted type 8-10
gauge with 90° countersunk heads, angle of
bend 95°-100°, length 6.5/8 in., thread diameter
.144 in., 40 threads per inch, thread form British
Standard Cycle.
17. Wheel Building and Truing
The spokes are laced one over two and the
wheel rim must be built central in relation to the
outer faces of the distance collars 39315 and
39323. The rim should be trued as accurately as
possible, the maximum permissible run-out
both sideways and radially being plus or minus
1/32 in.
18. Tyre
The standard tyre is Dunlop 3.50-19 in.
Universal tread.
When removing the tyre always start close to
the valve and see that the edge of the cover at
the other side of the wheel is pushed down into
the well in the rim.
When replacing the tyre fit the part by the
valve last, also with the edge of the cover at the
other side of the wheel pushed down into the
well.
If the correct method of fitting and removal
of the tyre is adopted it will be found that the
covers can be manipulated quite easily with the
small levers supplied in the toolkit. The use of
long levers and/or excessive force is liable to
damage the walls of the tyre. After inflation
make sure that the tyre is fitting evenly all the
way round the rim. A line moulded on the wall
of the tyre indicates whether or not the tyre is
correctly fitted. If the tyre has a white mark
indicating a balance point, this should be fitted
near the valve.
19. Tyre Pressures
The recommended pressures for the rear tyre
are 16 lb. per square inch for wheel loads not
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