Refitting The Main Bearings; Timing Cover; Timing Gears - Triumph SPEED TWIN 1945 Workshop Instruction Manual

Servicing Crankcase
R e f i t t i n g t h e m a i n Bearings. O n all models previous t o 1954 and the 1954
model ST, a bearing chipshield
i s
inserted before the timing side main bearing and
a disc and circlip following t h e bearings.
It
w i l l be found easier t o fit the bearings
o n all models If t h e crankcase is heated I n the area of the bearing housing before
pressing t n e bearings i n t o position.
Timing Cover. This cover houses a very important bush which seals the crank-
'shaft
oil
supply. If this bush
i s
worn, t h e pressure from the oil pump w i l l be released
directly i n t o t h e timing cover, thus reducing the quantity and pressure of oil t o the
big ends. The bush should always be changed when overhauling the engine. Press
o u t t h e old bush and press
in
t h e new bush. Reamer i n position. (New crankshaft
end diameter =0.622"
-
0.623". Bush internal diameter= 0.6235"
-
0.624").
Timing Gears. Timing gear wear
is
negligible
;
the only part which will require
changing after considerable mileage
i s
the intermediate gear bush. To change,
push o u t the old bush and insert the new. It may be necessary t o lightly reamer
t h e bush t o suit t h e spindle diameter. If the timing gears
a r e
noisy,
it
i s
futile
to
purchase an odd gear t o overcome this fault. A far better plan
i s
t o consult your
Triumph dealer w h o w i l l be able t o remedy this trouble by selective assembly of
gears from his stocks.
Oil Pump. As previously stated under "Lubrication Maintenance", Page 25, only
t h e o i l pump block w i l l show signs of wear after considerable mileage. When doing
an engine overhaul, however, completely dismantle the pump by removing the t w o
plungers and the t w o body plugs when the non-return ball valves and springs will be
released. Wash t h e pump body and examine the bail seatings ; i f these show signs
o f heavy indentation, pitting o r wear t o one side of the seat, they can be re-cut w i t h
a 45' cutter o r d r i l l suitably sharpened. inspect the balls and springs and if i n doubt
about their condition, new one: should be fitted. When replacing the bails, they
should be given a sharp tap onto t h e i r seatings t o ensure a good
seat.
After
assembling t h e pump, submerge the body i n o i l and operate the plungers. This
w i l l prime the pump and
a t
the same time give some indication of i t s pumping ability.
Oil Release V a l v e
and
I n d i c a t o r . The illustration. Fig. 5, indicates t h e con-
struction of the valve and indicator and should be closely followed during the dis-
mantling and assembly procedure. First remove the valve cap and indicator assembly
by unscrewing f r o m the main body when the piston valve can be withdrawn. T o
remove the indicator, grip the shaft nut and unscrew the shaft from
it.
W i t h d r a w
the shaft t o release the springs and rubber seal. Carefully clean ail parts and ensure
that t h e piston valve works freely i n t h e body. D o not tamper w i t h the springs by
stretc'hing t o increase the tension as t h e spring poundage i s set t o give the correct
pressure. W h e n replacing the indicator always fit a new oil
seal.
Assemble i n t h e
following manner : Place indicator shaft i n t o the cap and slide the new o i l
seal
over
t h e shaft followed by the main spring (large) and auxiliary spring (small) and finally
screw o n the shaft nut. O i l the piston valve and enter into the body, position t h e
joint washer on t h e body and screw o n the cap assembly.