Chapter 4. Carburetion; Carburetor; Carburetor Tuning - Yamaha SRX440 1980 Service Manual

1980 SRX440
CHAPTER 4. CARBURETION
4-1. CARBURETOR
A. Carburetor tuning
1. Standard specification
The carburetor is set at the factory to
run at temperatures of O°C to - 20°C
(32 ° F to - 4 ° F) at sea level. If the
machine has to be operated under con-
ditions other than specified above, the
carburetor must be reset as required.
Special care should be taken in carbure-
tor setting so that pistons will not be
holded or seized.
Free play between outer tube end and
adjuster:
0.5
~
1.0 mm (0.2
~
0.4 in)
3. lock nut
2. Adjuster 1. Outer wire
#115
#85
#260
Power jet
Pilot jet
Main jet
2. Throttle cable and throttle valve open-
ing
a. Set the throttle cable adjuster so that
the free play between the throttle cable
outer tube end and adjuster when the
throttle is closed (idling) as specified
below:
b. Remove the intake air silencer, and pull
the throttle lever while lookin into the
bores of both the right and left carbure-
tors. Set the throttle cable adjuster
SO
that both throttle valves to open at the
same time.
Also make certain that the throttle
valves reach full throttle position at the
same time.
c. Repeat the operation specified in a. and
b. above. When the adjustment is com-
plete, be sure to install the intake air
silencer.
W A R N I N G : - - - - - - - - - - ,
Throttle cable must not be lubricated in
any way. It must be routed correctly to
avoid throttle problems that may lead to
an unsafe condition during operation.
·1. Check to see synchronising
160
2.0 turns out
1.500
r/rntn
30
±
1 mm
11.18
±
0.04
in)
Pilot screw
Starter iet
Idling engine speed
"Hoet
height
C A U T I O N : - - - - - - - - - - ,
If the air silencer box is removed from
the carburetors. the change in intake
pressure will create a LEAN MIXTURE
that may result in severe engine
damage. The air silence box has no
effect on performance characteristics
and it must be secured to the carburetor
during carb tuning and adjustment. It
must always be in place when the
engine is operated. Examine the
silencer regularly for cleanliness and
freedom from obstruction,
4-2