Decarbonising; Rocker Adjuster Pin - Triumph SPEED TWIN 1945 Workshop Instruction Manual

R o c k e r l d j u s t e r
Pin. Slacken off t h e adjuster pin locknut and screw down
adjuster u n t i l it just contacts the valve tip. For remaining details o n models ST,
6T
and T I 0 0 read (a) and (b) and f o r T I 1 0 and TR5 read (a) and (c).
(a) W h e n t h e adjuster contacts t h e valve tip, hold t h e adjuster firmly w i t h t h e
spanner and tighten up the locknut w i t h the other spanner. G r i p the rocker
adjuster between thumb and forefinger and move t h e rocker sideways to
t e s t for freedom of movement. N o w test t h e up and down movement where
t h e clearance between the adjuster and valve t i p should be just perceptible.
(b) I n o r d e r t o obtain the 0.010" (0.26 mm.) clearance, fi r st take particular n o t e
o f t h e squared end of the adjuster and w i t h both spanners i n position, slacken
t h e locknut slightly, taking care n o t t o move the adjuster whilst doing so.
N o w slacken off the adjuster
ONE
FLAT
( i
turn) and, maintaining
it
i n t h e
n e w position, re-tighten the locknut.
Carry o u t the same procedure w i t h each tappet.
(c)
T h e clearance on the exhaust valve can be estimated by f i r s t adjusting t h e
tappet as i n (a), paragraph (one). T o obtain the 0.W4" (0.10 mm.) clearance,
slacken back t h e adjuster
HALF A
FLAT
(+
turn). This may be slightly i n
excess o f the clearance figure but the e r r o r i s o n the right side. For the inlet
clearance, only slightly slacken off the adjuster so that when the rocker is
held between thumb and forefinger and operated i n an up and down move-
ment, a distinct "click" can be hesrd when the adjuster strikes the valve tip.
The engine should be decarbonised only when it shows definite signs of requiring
this attention. Falling off i n power, loss of compression, noisy operation, and more
difficult starting are all signs that the engine needs decarbonising. The engine w i l l
probably r u n at least ten thousand miles (15,000 kms.) between t h e decarbonising
periods.
It
should be noted that it i s entirely unnecessary t o remove the cylinder block
w h e n decarbonising the engine. W e strongly recommend that this part is n o t
taken off unless it is proposed t o
fit
new piston rings o r do some other w o r k o n
t h e engine which necessitates the r e m ~ v a l o f the block. The engine w i l i run more
smoothly and give better service if the piston rings are left undisturbed.
Gasket sets are available for all models, and it i s recommended that the correct set
f o r t h e model i s obtained before commencing the work.
Before commencing the operation, clean off any dirt, grease, etc., w i t h paraffin o r a
suitable degreasing agent. Secondly, obtain t w o boxes, one for the cylinder head,
etc., and the other for nuts, washers, etc. By doing this the operator w i l i not have
t o search rhe four corners of the garage for the vital nut t o complete the job.