alternative, use an Arbour press with one flywheel supported by two
stout steel bars placed on four blocks, which is the best method if suitable
equipment is available.
Removing the timing side bush. Firmly support the crankcase on the
timing cover end, press out the bush from inside the crankcase. To fit a
new bush, reverse the crankcase, press in the new bush, the inner edge
should be flush with the crankcase. This bush is fine bored in production
with the bush in position. The new bush should be reamed to .8752" to
.8757".
Timing side bearing sleeve (022352). This is a press fit on the shaft, the
normal outside diameter is 1.2581" to 1.2585".
Timing side bearing (022351). To remove bearing s]eeve, apply heat to
the crankcase, drop the crankcase on the bench, when the bearing sleeve
will fall out.
Camshaft bushes. See details given for 'Heavyweight Single Cylinder
Models'.
Rocker box. For dismantling instructions refer to 'Heavyweight Single
Cylinder Models'.
Assembling the flywheels. These must be assembled with a suitable hand
press. Tighten the crankpin nuts with a torque spanner set to 240 ft. lbs.
The shafts should run true to .001" to .002".
Cylinder head joint. As a gasket is not used, the joint is remade by grind-
ing the cylinder head on to the barrel by moving the head to and fro
through an arc of about 30° and not in a full circular motion. Continue
grinding until a full matt surface on both parts is shown.
Valve timing. Up to 1959 cam wheels marked SH were used with part
number 018333 and 022567 for the inlet and exhaust respectively, Both
cam wheels are marked for correct assembly. Install the inlet cam with
the No. 2 mark to register with the mark on the small pinion. Use No. 1
mark for exhaust to also register with mark on small pinion,
The push rod clearance for these cams is nil for the inlet and .005" for
the exhaust (engine cold). The inlet push rod should be just free to revolve
by finger application. The clearance of .005" for the exhaust represents
one flat on the adjusting screw away from the nil clearance setting.
Position the engine for push rod adjustment as described for Touring
Heavyweight Models.
The valve timing on average is as follows:
Inlet opens
„ closes
Exhaust opens
„ closes
59° b.t.d.c.
69° a.b.d.c.
74° b.b.d.c.
48° a.t.d.c.
These readings are taken with the valve .001" off its seat with running
push rod clearance. The valve lift is .375".
Valve timing—1960. A more efficient type of inlet cam was introduced
for and after the 1960 season. The inlet cam is marked C1, Part No.
024534, and is used in conjunction with the 1959 exhaust cam 022567.
The valve timing with the new cam allows the inlet to open at 67° b.t.d.c.
and to close at 80° a.b.d.c. with a nil clearance and the valve .001" off its
seat. The valve lift is .428".
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