4-6
MACHINE TUNING
JUDGING AIR/FUEL MIXTURE
For proper carburetor tuning, it is necessary to
know how to judge the air/fuel mixture made in the
carburetor; whether too rich, too lean or properly
mixed. Given below are the symptoms observed
when the engine is not supplied with the proper
air/fuel mixture ratio from the carburetor. Check
each item as reference for judging the air/fuel mix-
ture condition.
When air/fuel mixture is too rich
1) The engine noise is dull and intermittent.
2) The engine condition becomes worse when the
starter is applied.
3) The engine condition becomes worse as it is
warmed up.
4) The engine condition improves when the air
cleaner is removed.
5) The spark plug is fouled with carbon (wet and
oily).
6) The exhaust gas produces heavy smoke.
When air/fuel mixture is too lean
1) The engine overheats.
2) The engine condition improves when the starter
is applied.
3) Acceleration is poor.
4) The spark plug is burned white.
5) The speed of the engine fluctuates and lack of
power is noticed.
6) Detonation and pinging are experienced.
TUNING PROCEDURE
The following indicates the correct tuning procedure
for this motorcycle. Understand the procedure by
first riding the motorcycle where it will be used and
adjust the engine to the best condition after judging
the air/fuel mixture.
Carburetor standard setting
Main jet:
#128
Jet needle: 24NAAH-3rd
Slow jet:
#50
Air screw: 2 turns out
INCLUDED PARTS AND OPTIONAL PARTS
Main jet
Air/fuel
SIZE
mixture
Lean
#115
#118
#120
* #122
#125
#128
* #130
#132
* #135
#138
#140
#142
Rich
#145
Slow jet
Air/fuel
SIZE
mixture
Lean
#45
#48
#50
#52
#55
Rich
#58
Jet Needle
Air/fuel
SIZE
mixture
Lean
24NCDK
24NAAK
24NCDJ
24NAAJ
24NCDH
24NAAH
24NCDG
24NAAG
24NCDF
Rich
24NAAF
NOTE:
SHADED : STANDARD
*
: INCLUDED PARTS
NONE
: OPTIONAL PARTS
P/NO
09491-23027
09491-23028
09491-24030
09491-24031
09491-25019
09491-25020
09491-26017
09491-26018
09491-27016
09491-27017
09491-28019
09491-28020
09491-29014
P/NO
09492-45032
09492-48013
09492-50023
09492-52011
09492-55017
09492-58001
P/NO
13383-03B90
13383-03B40
13383-03B80
13383-03B30
13383-03B70
13383-03B20
13383-03B60
13383-03B10
13383-03B50
13383-03B00
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