Float Height Adjustment; Diagnosis Of Carburetor; Mixture Adjustment - Suzuki RG250 Service Manual

•
5~5 FUEL AND LUBRICATION SYSTEM
FLOAT HEIGHT ADJUSTMENT
To check the float height, invert t he carbu retor
body. wit h the float arm kept free, measu re the
height
®
while floa t arm is just in contact with
needle valve by using cali pers.
Bend the t ongue
CD
as necessary to bring the
he ight
®
t o this value.
Float height
®
23.5
±
1.0
mm
099 00 ~2 01 02
Vernier calipers
NOTE:
When measuring float height, be sure t o
remove the gasket .
DIAGNOSIS OF CARBURETOR
Whether the ca rbu reto r is producing a proper
mixtu re of fuel and ai r can be checked by making
a road test (si mu lating the way the user operates
t he machine ) with a standard spark plug (refer to
serv ice data) fitted to the engi ne. After the road
test , remove the spark pl ug, and observe the ap-
pearance of the plug as well as the surface of the
piston crown. The color observed tel ls whether the
mixture is too rich o r too lean. When replacing t he
spark pl ug, consult the page 2-5.
MIXTURE ADJUSTMENT
• Th is adjustment is eff ected mainly by main jet
and jet need le.
Befo re doing so, check to be sure that the float
level is correctly set and that the overflow pipes,
breather pipes, inlet hose and air cleaner are in
sou nd condition.
• Find out at which th rottle position the engine
lacks power or otherwise performs poorly _ Drive
the machine at the th rottle position for a
dist ance of about 10 km, afte r wh ich the spark
p lug and piston crown should be inspected fo r
co lor and appea rance.
• The mixtu re can be made "richer" or "leaner"
in three ways: namely, by alterring main jet, jet
needle and pilot ai r screw. Effectiveness of
these ways de pends on the th rottle posi t ion, as
shown in this chart.
/
Throttle opening Yo
Pilot air screw
Jet needle
Main jet
NOTE:
14
*
I
®
Upside
Full
If the machine is tested at 1/ 2 throttle result-
ing in a co lo r and appearance indicating a
mixture that is too rich o r too lean, perform
adjustment by means of jet needle and pilot
air screw.