Specifications
Chapter 5 Wheels, brakes and tyres
81
3 Front wheel: removal
1 With the machine supported on the centre stand, block the
stand and crankcase to raise the wheel clear of the ground.
2 Detach the speedometer drive cable at the wheel, by un-
screwing the knurled gland nut which retains it. Remove the
front brake cable.
3 Remove the wheel spindle nut and split pin, and withdraw
the spindle with the aid of a tommy bar. The wheel can now be
lowered clear of the forks and put to one side.
4 Front brake: examination and renovation
1 With the wheel removed from the forks, as described in the
preceding Section, the brake plate assembly can be removed
from the drum.
2 Examine the drum surface for signs of scoring or oil con-
tamination. Both of these conditions will impair braking
efficiency. Remove all traces of dust, preferably using a brass
wire brush, taking care not to inhale any of it, as it is of an
asbestos nature, and consequently harmful. Remove oil or
grease deposits, using a petrol soaked rag.
3 If deep scoring is evident, due to the linings having worn
through to the shoe at some time, the drum must be skimmed
on a lathe, or renewed. Whilst there are firms who will
undertake to skim a drum whilst fitted to the wheel, it should be
borne in mind that excessive skimming will change the radius of
the drum in relation to the brake shoes, therefore reducing the
friction area until extensive bedding in has taken place. Also full
adjustment of the shoes may not be possible. If in doubt about
this point, the advice of one of the specialist engineering firms
who undertake this work should be sought.
4 If fork oil or grease from the wheel bearings has badly con-
taminated the linings, they should be renewed. There is no
satisfactory way of degreasing the lining material, which in any
case is relatively cheap to replace. Measure the thickness of the
friction material; if it is worn at any point to or beyond the
specified wear limit, both shoes must be renewed immediately.
It is a false economy to try to cut corners with brake
components; the whole safety of both machine and rider being
dependent on their good condition.
5 The linings are bonded to the shoes, and the shoe must be
renewed complete with the new linings. This is accomplished
by folding the shoes together until the spring tension is relaxed,
and then lifting the shoes and springs off the brake plate. Fitting
new shoes is a direct reversal of the above procedure.
6 Before refitting existing shoes, roughen the lining surface
sufficiently to break the glaze which will have formed in use.
7 The camshaft can be displaced for greasing prior to
reassembly, after removing the actuating lever. No further
attention is normally required. Note the alignment marks on the
camshaft splined end, and on the lever. These must align on
reassembly.
Fig. 5.1 Front wheel and brake - component parts
1
2
3
4
5
6
7
8
9
10
Wheel spindle
Spacer
Hub
Distance piece
Wheel rim
Tyre
(2.50-
18-4PR)
Inner tube
Rim tape
Speedometer drive gear
Fibre
washer
11
Brake plate
12 Brake shoe -2 off
13
Camshaft
14
Return spring -2 off
15
Actuating arm
16
Threaded plate
17
Spring
18
Castellated nut
19
Washer
20 Seal
21 Seal
22 Bolt
23 Screw
24 Split pin
25 Trunnion
26 Adjusting nut
27
Bearing-2
off
28 Spoke set
29 Spoke set