BSA D14/4 BANTAM SUPREME D14/4 BANTAM SPORTS, Workshop Manual

Page: 37 / 120

D14/4 ENGINE B11
FIG. B11.
The kickstart mechanism can now be removed from
behind the clutch, by releasing the clock-type spring
and lifting the quadrant clear.
Gently withdraw the layshaft with its fixed top and
second gear, and lift out the remaining layshaft second
and bottom gear.
To enable the mainshaft gears to be removed it will
be necessary to take off the cam plate mounting
bracket. Bend back the tab washers and take out the
two fixing bolts. Carefully lift out the cam plate,
mainshaft sliding gear and selector forks, taking care
not to lose the two loose fitting rollers which locate
the selector forks in the cam track.
The cam plate plunger spring, seating and ball are a
loose fit in their socket at the back of the case, and
should be removed now to prevent any loss of parts.
Hold the crankcase assembly firmly in a soft-jawed
vice gripping the gearbox mainshaft.
REMOVAL OF CLUTCH HUB
With the gearbox mainshaft held firmly in a soft-
jawed vice, remove the clutch centre nut and washer,
which will release the clutch centre pinion, thrust
bearing and two washers and the clutch chainwheel.
The kickstarter ratchet pinion is held on to the
chainwheel by a circlip which, when removed,
releases the pinion, spring and retainer.
The gearbox mainshaft complete with its fixed first
gear, and third gear, can now be withdrawn.
GEARBOX INSPECTION
The mainshaft third gear is held against the mainshaft
first gear by a circlip. This gear should spin freely on
the shaft without excess play.
The layshaft second gear is held against the layshaft
fixed gear by a similar circlip, and this gear should
also spin freely without excess play.
All dogs and teeth should be free from signs of
excess wear and pitting, and the sliding gears should
be a good sliding fit on their splines. The diameters of
the shaft that run in bushes should be smooth and
polished, free from signs of seizure and picking up.
The selector forks should be lightly polished on
their forks, and should run freely in their sliding gears.
The selector fork rod should be a good fit in the
right-hand crankcase and should be straight. The
selector forks should slide up and down the shaft, if it
is suspected that the shaft is bent it can be checked by
rolling on a surface plate or a piece of plate-glass.