Dismantling, Preparation And Assembly Of The Engine Units; Rocker Boxes; Valves And Springs - Triumph SPEED TWIN 1945 Workshop Instruction Manual

Dismantling Cylinder Head
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R e m w e f i o m t h e tappet b l o c k ~ .
C y l i n d e r B l o c k . Unscrew t h e eight nuts; secure t h e tappets i n the blocks by
placing a rubber wc.dge between them, taking care n o t t o use undue force. Carefully
l i f t the cylinder block off t h e pistons.
Pistons. Remove a circlip from each piston and then press t h e gudgeon pins o u t
f r o m t h e opposite end.
The fit o f t h e gudgeon pins i n t h e pistons
i s
fairly tight;
i f a gudgeon pin extractor is available, it should be employed. The pistons should
be suitably marked o n t h e inside t o ensure replacement t o t h e i r original positions.
M a g n e t o o r D i s t r i b u t o r . Unscrew t h e securing nuts and remove the unit.
C r a n k c a s e b o l t s . Remove t h e remaining bolts and screws. NOTE.-Do n o t
forget t o remove t h e t w o screws f r o m t h e internal bosses.
C r a n k c a s e F i l t e r . Slacken off t h e vice jaws and remove t h e crankcase. Unscrew
t h e four nuts holding t h e filter base and remove the base and f i l t e r gauze.
C r a n k s h a f t a n d Camshafts. T o split t h e crankcase, bump t h e drive shaft o n t o a
piece of wood when the t w o halves w i l l readily part. The crankshaft and camshafts
can n o w be removed.
In the drive side crankcase t h e breather rotary valve and spring i s located i n the
camshaft bush.
Care should be taken n o t t o lose these.
DISMANTLING, PREPARATION A N D ASSEMBLY O F
T H E E N G I N E U N I T S
C Y L I N D E R H E A D
R o c k e r Boxes. Unscrew t h e four nuts and then the four screws when the rocker
boxes can be removed f r o m the head. Wash t h e rocker boxes thoroughly and inspect
the parts for wear. Check t h e ball ends, adjuster pins, and rockers o n the spindles
for wear.
Examine t h e rocker boxes for cracks o r pulled studs.
Normally, wear
on the rocker spindles
is
negligible
as
they are fully lubricated.
The adjuster pins
sometimes show slight wear
or
indentation which can be removed by lightly stoni;lg
the hardened pad. If t h e markings are t o o deep, t h e pins should be replaced.
Carefully inspect the ball ends, i f the spheres are mis-shapen t h e bail ends must be
changed. This operation w i l l necessitate dismantling t h e rocker box o r boxes.
T o do this, knock o u t the rocker spindle f r o m t h e threaded end using a hide hammer
o r similar s o f t t o o i t o prevent damage t o the thread. A f t e r withdrawing the rocker
levers the ball ends can be pressed o u t o f t h e housings and t h e new ball-ends fitted.
W h e n replacing t h e spindles, a new rubber seal must be employed: Fig. 6 shows
the position o f the various washers.
Valves a n d Springs.
Compress the valve springs sufficiently w i t h
a
compressor
too!, when t h e split cotters can be ezsed away w i t h a narrow screwdriver o r similar
tool.
Release t h e t o o l and withdraw both valve and valve springs.
Repeat t h e
operation
to
t h e other valves; mark the valves f o r replacement. Inspect the springs
for signs of fatigue (Free length Outer, 2.031" (5.16 cms.); Inner, 1.625" (4.13 cms.)
);
i f i n doubt,
a
new
s e t
of springs should be obtained.