BSA B33 - Removing the Cylinder Head

fig. l6h,
'Monobloc' cafturetter
40
tho
piston
is
at t.d.c,
on the coEpression
stroke,
i.e,, with
both valves
closed.
This will
plevent
any
pressure
on
the valves dudng
the
operation,
Prelimfuary
Work,
It is
6rst ne4essary
to
rcmove
the
pehol
tank. Turtl
of the
petrol
tap aDd
detach
the
oehol
pip€.
The
tank is secured
to the
frame
by a
bolt
through
the steering
head lug
and two
bolts
to spe.ial
lugs at the
rear
of the frame
top tube.
Whe[ thestbolts
are removed
the tank
can be
taken ofl.
Note the
corect
order of
the rubber
mountings
for reassembly
purposer.
On swinging
arm models.
First
remove
the
Detrol tank
strap which
is located
under
lhe front
of tbe
tank
aDd is
held in
position
by two duts.
The
central
taDk locking
bolt can
then
be removed
when the
rubber
cover in
tha
top of the
tank
is
pulled
otr
Next
detach
the high tenrioa
lead
and iemovo
thc
sparking
pl'lg.
Disconoect
tle
steadyiDg
ståy
from the
cyli[der head
to the
frame, aDd
then take
offcarburetrer
by æmoving
the air
nange nuts,
(When
fitted
with
an
air-cleaner
see
page
35.)
By unscrewing
the ring
out at
the top
of the carburetter
the slides carl
be
pulled
dght out
and tied
to the
frame
top
tube out
of the
way, while
the main
body
of the
instrument
can
be removed,
Take
oare trot
to damage
th€
carburetter
flange washer,
The
pipe
atrd siletrcer
can be removed
complete,
the
pipe
itsef
b€iDg
a
push
fit in
the cylinder
head.
Remoyiog
the Cylinde.r H€ad.
(For
Coop. and
Gold
Star
models
see
pages
48and
50 &spectivelr.
DiscoDne4t
the
oil fe€d
pipe
to
thc rocker spildles
aDd
the oil
retu$
pip€
ftom the
rocker
box to tåe
crankcase.
Note
that
t-h€
union søews
for the oil
pipe
to the
rocker spiadles
have
a m|rch smaller
hole in the
side than
the union
screw
for.
the
retum
pipe--€
point
to re4ember
when reasseEbling.
The
exhaust
valve lifter
cable cao either
b€ discoDoectcå.
or
the
exbaust
rocker
box cover
removed
leavilg
the
cable htact.
Remove the
inlet
valve rocker
box cover.
SlackeD the
castellated
glald
rut
secudng
the
pulh-rod
cover
tube to
the
qylitder
head
(usiDg
the sp€cial
.C'
,iil
jrl
Ne
q@
ry,
t
t
,t
t