Faulty Gear Selection; Quadrant Plunger Sticking; Camplate Plunger Sticking - Triumph SPEED TWIN 1945 Workshop Instruction Manual

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GEARBOX
The gearbox employed has four speeds and is very robustly constructed.
It
w i l l
require very little attention, and, if its o i l change intervals are strictly adhered t o
and the security of i t s clamping b o l a occasionally checked, the life of the gearbox
w i l l be greatly prolonged.
For the rider who wishes t o use his machine i n one o r more of the various com-
petitions or for road racing, a set of gears can be made available t o suit the particular
conditions. To change from STANDARD t o W I D E ratio, four gears are required,
namely-mainshaft high, mainshaft second, layshaft high and layshaft second. T h e
speedometer driven gears will also have t o be ctianged t o correct the speedom'eter
t o gearbox ratio. To fit CLOSE ratio gears a complete set is required and
as
no
provision is made for the speedometer gears, a sealing plug i s supplied.
A
tacho-
/
meter driven off the exhaust
a m
gear is employed for the purpose of checking the
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engine revolutions when close ratio gears are fitted. On page
207
an "Engine
Revolution" and "Gear Ratio" chart w i l l be found which will assist the rider in
choosing a suitable combination of gears.
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Briefly, the gearbox operates in the following manner:
Gear selections are made by depressing o r raising the pedal. The pedal is attached
t o the plunger quadrant which is spring loaded o n either side of its axis. After the
pedal has been operated, it will automatimlly return t o the central position for the
next selection. When the pedal i s depresed the upper quadrant plunger moves
under the guide plate, whereas the lower one, being released, connects with the
gear operating quadrant which
i s
geared t o the camplate.
The camplate is rotated by the gear quadrant, the movement being arrested by a
spring loaded plunger which
i s
sprung into a notch in the camplate periphery. As
the camplate rotates, the gear selector forks which are connected, move along their
spindle and in turn shift the gears. Fig. 24 shows clearly all the working parts and
before attempting t o dismantle the gearbox, the illustration should be carefully
studied.
F A U L T Y GEAR S E L E C T I O N
A badly adjusted clutch is one of the chief causes of faulty gear selection.
Always
ensure that the clutch plates spin true and that the correct grade of oil is employed
(See page 200 for further information).
Gearchange pedal springs may be fatigued o r broken, thus preventing the pedal from
centralizing itself. Remedy+hange both springs.
Quadrant Plunger Sticking. T o remedy, remove the plunger and polish the
bearing surface with smooth emery until the plunger will move freelj in
i t s
housing.
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It is a good plan t o renew the plunger springs i f this fault occurs.
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C a m p l a t e Plunger Sticking. To remedy, remove the domed nut from.the
bottom of the gearbox casing and apply the same remedy as @ r Quadrant Plungers.
Slackness of the nuts securing the kickstarter assembly o r clutch centre.
As both these parts are attached t o the gearbox mainshaft, either becoming loose
would allow the mainshaft
t o
h a t and cause a faulty selection. Remedy--obvioirs.