Triumph TR4A - Adjusting and Synchronizing Twin Carburetor Installation; Float Chamber Fuel Level

RUNNING
ADJUSTMENTS
Adiusting
and Slnchonising
TrYin Carbuettor
Installation
Loosen
the
clamping bolts on
the tbrottle spindle
couPlings
between
thg
two instruments.
Next, unscrew
the throttle
stoP
screw
to
permit the throttle in each carburettor
to close com-
pletely.
aid
tighten the clamping bolts
on the
couPlings between
lhe sDindles of
the two carburetlors.
Screw
in
the throttle stop screws
(3)
to
rbe
Point
where the
eod o[
the screw
is
just
contacting the stop
lever
attached
to
each
throttle spindle.
From this point
rotate
the stoP screw
in each carburittor
one complete
turn
to oPen the
throttles
ar equal
amount
to
provide
i basis
from which
final speed
of
idle can
be set.
Having
reconnected the
throttles and set
each oPen
an
ecual ambunt.
rezulate
the
iet
adiusting
scr€ws
(13)
in lhe
in'srruments
as deiailed
undei the lieadirig "setting
the ldle".
i.e,,
three tums
down from the
Point
where
the
jet
orifice
comes
into contact
with the base of
the air valve
(18).
NOTE ;
Remember
that the idle quality
dePends
to a large
extent
upon
the
general
englne
condition and
such
points
u. rappit
adjust;ent. spaik plugs,
and ignilion
iiming
should be
inlpected if
idling is not
stable. It is
also in-
portant
to eliminate
any leaks
in the
induction system
Float Chamber
Fuel LeYel
(Fig.
48)
To check
the
float level, remove
the carburettor
from the
engine
and
remove the float
chamber. Invert
thc carburettor.
Chlck
that the highest point
of
the float, when
the needle is
Fig'
't8
apainst
irs seating,
is 073"
(18
5 mm,)
abote the face of
the
m-ain body.
Re-sit the
level by carefully
bending
the ta8
which
contacts ihe end
of the needle.
The addition
of a thin fibre
washer under
the needle
valve seat
will effectively
lower the
fuel
level.
a.7{
l8'5
M
35