off the spindle. The outside rocker with spindle can be pulled out
together with the steel sleeve 017292.
Either one or two felt sealing rings used midway between the two
rocker axle bushes can be prised out with a sharp pointed tool. As a guide,
measure the protrusion of the inner bushes before removal.
Removing the rocker bushes. If the rocker box is slightly heated, the
rocker bushes can be drifted out without difficulty.
Refitting the rocker bushes. It should be explained that the location of
the rocker bushes controls the end play between the bushes and the
rockers. Re-heat the rocker box and fit one of the inner bushes, chamfered
end first. The bush should be to the amount measured before dismantling,
which usually is approximately
E". With the four bushes assembled and if
new ones are used, they should be reamed to s " + .00075" — .00050"
in situ. Introduce the felt ring(s) into the groove. A taper mandrel inserted
into the felt ring is desirable to compress the felt to enable the steel
sleeve to pass through. Put the steel sleeve (with some oil on it) over
the rocker spindle with the outside rocker attached, carefully work the
assembly through the bushes and felt ring.
Refit the inner rocker and using again the box spanner firmly tighten
both nuts. If the rocker assembly is tight to move, a light tap on the outer
end of the rocker spindle with a light hammer will move the bush and give
a free movement. The end play should just be discernible. If the end play
is in excess, take out the spindle assembly and tap outwards one of the
bushes.
NOTE—The rocker arm valve end should be central with the valve stem.
Separating the crankcase. With the crankcase out of the frame start by:
Removing oil pump guide pin and sleeve (6) Fig. 9.
Removing four bolts securing cap for oil pump plunger and pull out
the plunger.
Removing bottom and front crankcase bolt.
The crankcase can now be separated, as the small timing pinion will
pass through the timing side bush; the pinion can be dealt with later.
Separating the flywheels. To do this use the tool and method described
for the 250 c.c. Scrambler models.
Removing small timing pinion. The nut securing this pinion has a left-
hand thread. The pinion is a taper fit on the shaft and usually requires
an extractor tool B2151. When using any kind of extractor, apply light
pressure on the withdrawal part of the tool, then give the end a sharp
blow with a hammer, the shock will dislodge the pinion. A new pinion
will absorb backlash and cure timing gear rattle.
Removing the drive side bearings. Gently heat the drive side crankcase
and drift out both bearings. Check both bearings for roughness caused by
pitted race tracks. Renew the bearings at the slightest sign of roughness,
the bearing should spin by hand rotation smoothly and quietly.
Removing the timing side bush. Support the half crankcase firmly, press
out bush from timing cover end, the locating peg will come out with bush.
If a new bush is used, ream in situ to 1.125" + .0005" — .0000". Replace
locating peg when bush is in position.
Camshaft bushes. These rarely wear, do not be misled by waggling the
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