Carburetor Tuning; Principles Of Carburetor Tuning - Suzuki RM-Z250 Owner's Service Manual

CARBURETOR TUNING

The carburetion of your motorcycle is carefully selected after extensive testing. You will find that the carbu-
retion will function smoothly under many varied operating conditions. For best results we recommend that
the adjustments and carburetion jetting be left "as is" from the factory.
Some riders may operate their motorcycle under extreme operating conditions such as; very high altitudes
or extreme cold and hot temperatures. In these circumstances the jetting of the carburetor or other adjust-
ments may need to be altered slightly. Riders who are not familiar with the operation and jetting procedures
of the KEIHIN carburetor should have their local authorized Suzuki dealer perform these alterations.
Mechanically experienced riders can alter the carburetor settings based on the following information and
specifications.

PRINCIPLES OF CARBURETOR TUNING

CARBURETOR COMPONENTS AND FUNCTIONS
The carburetor consists of a number of parts as shown below. The asterisk (*) marked parts are precisely
machined, which meter the intake air (oxygen) and fuel so that the air/fuel mixture ratio is controlled accu-
rately. They can be divided by three operation-related groups; slow system, intermediate system and main
system, and they achieve their functions in each corresponding throttle opening range. It is necessary to
have a full understanding of them for proper carburetor tuning.
CARBURETOR SPECIFICATIONS
1 * Main jet (M.J.)
2 * Slow jet (S.J.)
3 * Jet needle (J.N.)
4
Starter jet
5
Slow air jet (S.A.J.) #100
6
Leak jet
7 * Pilot screw
Throttle stop
8
screw
9
Float height
Setting parts
Main jet #165
Main jet #175
Jet needle NLCT
Jet needle holder A
MACHINE TUNING 4-2
4
#170
#42
NLDT-4th
#75
#45
2 turns back
Adjust to the speci-
fied idle speed.
8 mm (0.31 in)
Parts No.
09491-33009
09491-35009
13383-10H40
13220-35G00