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ROYAL ENFIELD WORKSHOP MANUAL

1. Description of Frame

The frames used on the above models are

basically  identical,  with  swinging  arm  rear
suspension, but there are some small differences
in the lugs for engine attachment, the method of
attachment  of  the  pivot  point  for  the  swinging
arm  and  in  the  width  between  the  brackets
supporting the upper ends of the rear suspension
units.  For  part  numbers  of  frames  see
appropriate spares lists.

The frame is built throughout of cold drawn

weldless  steel  tubing  with  brazed  or  welded
joints,  liners  being  fitted  where  necessary  for
extra  strength.  All the  main frame  members are
made  of  chromemolybdenum  alloy  steel  tubing
which  retains  its  strength  and  resistance  to
fatigue after brazing or welding.

The swinging arm unit which forms the chain

stays  is  provided  with  large  diameter  phosphor
bronze  bushes  and  pivots  on  a  stout  steel  tube
which  is  secured  to  the  main  frame  by  a  long
bolt  passing  through  the  pivot  lugs.  Hardened
steel  thrust  washers  are  provided  to  deal  with
side  thrust.  The  torsional  rigidity  of  the
swinging  arm  unit  helps  to  maintain  the  rear
wheel upright in the frame and thus relieves the
wheel  spindle  of  bending  stresses  to  which  it  is
subject with other types of rear suspension.

2. Steering Head Races

The steering head races, 34085, are the same

at the top and bottom of the head lug and are the
same for all models. They are easily removed by
knocking them out with a hammer and drift and
new races can be fitted either under a press or
by means of a hammer and a wooden drift.

3. Removal of Rear Suspension Unit

The

rear suspension units are readily

removed  by  undoing  the  top  pivot  pin  nut,
driving  out  the  pivot  pin,  then  hinging  the
suspension  unit  back  on  the  lower  pivot  pin,
removing  the  lower  nut  and  pushing  the
suspension  unit  off  the  pivot  pin  welded  to  the
fork end.

4. Servicing Rear Suspension Units

(a) Proprietary Units. The proprietary units

fitted to most 1954 and all 1955 models are
sealed and servicing of the internal mechanism
can be carried out only by the manufacturers.

The rubber bushes in the top and bottom eyes

can  easily  be  renewed  and  the  spring  can  be
removed  by  pushing  down  on  the  top  spring
cover  so  as  to  release  the  split  collar  above  it.
After  removal  of  the  split  collar  the  top  cover
and spring can be lifted off. When reassembling,

the spring should be greased to prevent rust and

squeaking if it should come into contact with
either of the covers.

The standard solo springs have a rate of 100-

105lb. per inch and it is not difficult to compress
these by hand. Heavier springs having a rate of
130lb. per inch are available which may require
the use of a spring compressor, as shown in Fig.
2.

(b) Royal Enfield Units. Mark 1.

Enfield

rear  suspension  units,  Part  Number  34276  or
36451,  are  shown  in  Fig.  3.  Units  having  Part
No.  34276  are  fitted  with  springs  of  .252  in.
diameter  wire  (Part  No.  34284)  having  a  rating

of approximately 200lb per inch (when fitted on

Section H1 Page 2

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