Valve Push Rods And Cover Tubes; Crankcase Unit; Main Bearing; Scavenge Pipe - Triumph SPEED TWIN 1945 Workshop Instruction Manual

VALVE P U S H R O D S A N D C O V E R T U B E S
Push
Rods. Examine t h e end cups f o r chips around the edge, slackness o n t h e tube
and general wear inside t h e cups.
For any of these faults, t h e push rods must be
renewed. Bent push rods can cause undue noise and loss o f power, so before
replacing t h e m t o t h e engine, examine each one for straightness b y rolling t h e m o n
a t i u e surface which could show u p any irregularity.
C o v e r Tubes. I f o i l leakage is t o be avoided after an overhaul, always ensure t h a t
t h e ends are t i g h t o n the tubes and i n n o way damaged.
C R A N K C A S E UNIT
Main
Bearing. Remove the timing side bearing retaining ring (where fitted), and
press o u t t h e t i m i n g and driving side main bearings. This can be more easily accom-
plished by warming t h e crankcase. Wash thoroughly and d r y o u t w i t h compressed
air if possible
as this w i l l tend t o remove any small particles of foreign matter. Spin
t h e outer race t o test t h e bearing f o r roughness and then inspect the balls and track
f o r signs o f indentation o r pitting. Finally, test t h e end float which should be
negligible i n a good bearing. Replace i f any fault
i s
shown.
Crankcase. Wash t h e crankcase halves and inspect ail stud fixings f o r security and
t h e casting for cracks o r damage. Remember, i f one half of the crankcase
i s
damaged,
a
complete new crankcase must be purchased as these are machined i n pairs.
The
camshaft bushes normally shbw very l i t t l e signs of wear until a considerable mileage
has been covered. T o make a rough check, fit the camshaft i n t o t h e bearing and
ascertain the u p and down movement. if it
i s
desirable that the bushes are changed,
proceed as i n the following paragraph.
C a m s h a f t Bushes. T o remove t h e bushes i n the timing side half, heat
(lOO°C.
approx.) t h e crankcase around t h e bush housing when the bushes can be easily
pressed out.
W h i l e r h e case is s t i l l warm, press i n the new bushes, ensuring that
t h e o i l hole
i s
lined u p w i t h t h e driiiway i n the housing. The removal of t h e drive
side bushes is
a
l i t t l e more difficult and it is necessary t o cut a thread i n the bushes
w i t h
a
tap before heating the crankcase. W h e n this
is
done, re-insert the tap and
hold the square end in the vice when the crankcase can be gently tapped away w i t h
a hide hammer leaving the bush attached t o the tap. Located behind the rear bush
i s
the breather valve porting disc. Before replacing the new bush, ensure that this
disc i s correctly positioned o n the locating peg.
/
If the temperature of the crankcase half has dropped, re-heat and then press i n the
new bushes. The phosphor bronze bushes are machined t o size before pressing
in, and only t h e smallest amount of metal need be removed when reamering. To
ensure accurate alignment, t h e t w o halves should be bolted together before
reamering.
1
Scavenge Pipe.
Check this pipe f o r security and ensure that a perfect oil seal i s
made where
it
enters t h e crankcase at the pump position.
Failure at this point
would reduce oil scavenge t o the minimum.
I
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