Royal Enfield 250 CLIPPER, Workshop Maintenance Manual

Page: 25 / 96

ROYAL ENFIELD WORKSHOP MANUAL
PAGE 25
Service Operations with Engine out of
Frame
1. Removal of the Engine from the
Frame
Disconnect the battery leads.
Disconnect the petrol pipe.
Remove the petrol tank.
Remove the exhaust pipe.
Remove the engine steady.
Remove the rear chain and slide back gaiters.
Remove the carburetter complete.
Disconnect the generator leads at the junction
plugs.
Disconnect the contact breaker lead in the
toolbox.
Disconnect the clutch cable on the handlebar.
Unplug the sparking plug lead.
Remove the footrests and bar.
Remove the rev. counter drive from the
primary chaincase where fitted.
Remove the primary chaincase (Section C,
Subsection, 1).
Remove the generator cover (Section C,
Subsection 2).
Remove the rear fixing bolt complete with
distance piece.
Support the engine on a suitable block or box.
Remove the rear engine plates complete with
centre stand by taking out two
3
/
8
in. bolts.
Remove the front engine plates.
Lift the engine out of the frame from the
generator side (off side).
2. Dismantling the Crankcase
Having taken the engine out of the frame,
drain the oil from the oil tank and from the
gearbox by taking out the two hexagon headed
drain plugs at the bottom of the crankcase.
Dismantle the cylinder head, cylinder barrel,
piston, cam gear, generator and contact breaker as
described in Section C, and the clutch and gearbox
as described in Section E.
On the off (generator) side, undo four
1
/
4
in.
nuts "A" (Fig. 5, Section E) from studs and one
from the through bolt "B," near the bottom
between the generator and the gear change lever.
Undo two
1
/
4
in. bolts "C" in the crankcase
below the generator cover.
Remove the off (generator) side half crankcase
by tapping gently with a hide hammer behind the
contact breaker housing leaving the crankshaft in
the near (driving) side half case.
Press the crankshaft assembly out of the near
side half case by means of a hand press or by
using Special Tool No. E.6960.
3. Main Bearings
The main bearings consist of a roller bearing
on the off (generator) side, and a ball bearing on
the near (driving) side. The "350 Bullet" has in
addition a plain bearing situated between the ball
bearing, and the driving sprocket. Should the
bearing require attention or replacement on the
350 c.c. engine, it is recommended that the
crankcase, complete with crankshaft, is returned
to the works.
The proceedure for dealing with the 250 c.c.
bearings is as follows:
When the crankcase has been dismantled it
will be seen that the ball bearing stays in the near
side half crankcase, the outer race of the roller
bearing stays in the off side half crankcase and the
inner race of the roller bearing and the rollers stay
on the shaft.
To remove the ball bearing, first take out the
circlip which holds it in position in the near side
half case then heat the case to 100°C. by
immersion in hot water or in an oven after which
the ball bearing can be pressed or driven out.
When fitting a new ball bearing heat the case
only in the same way and drop the bearing in,
taking great care to keep the bearing square with
the bore. Do not forget to fit the circlip.
To remove the outer race of the roller bearing
from the off side crankcase, first heat the
crankcase to 100°C. and then tap the case on a
wooden base until the race drops out.
The inner race and rollers can be drawn off the
crankshaft, using a claw-type extractor. On later
models flats are provided on the distance piece to
accommodate the claws of the extractor.
When fitting a new roller bearing the outer race
is dropped into the off side half crankcase (with
the number facing away from the flywheel) after
the latter has been heated and the inner race is
tapped on to the crankshaft (also with the numbers
away from the crankshaft) with a hollow mandrel
.
D6A
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