Suzuki RM250 - Page 53

4-8 MACHINE TUNING
Jet needle
NOTE:
SHADED: STANDARD
*: INCLUDED ALTERNATE PARTS
NONE: OPTIONAL PARTS
1 Adjustment of slow system
1) Set the air screw as specified.
2) See if the selected slow jet is correct or not by
judging the air/fuel mixture. If air/fuel mixture is
rich, replace it with smaller one. If air/fuel mix-
ture is lean, replace it with larger one.
2 Adjustment of main system
With the throttle opened 3/4 to full, make main sys-
tem adjustment monitoring the air/fuel mixture con-
dition after completion of slow system settings.
* Make sure to adjust the main system before
adjusting the intermediate system.
3 Adjustment of intermediate system
Monitor the air/fuel mixture condition and adjust the
intermediate system by changing the needle clip
position.
4 Final adjustment of slow system
After a proper standard setting has been obtained
by the procedure 1 through 3, fine tune the carbu-
retor according to the actual race conditions.
1) Adjust the air/fuel mixture by turning the air
screw within 1/2 – 2 turns out.
2) If the mixture can not be adjusted by the air
screw within 1/2 – 2 turns out range, readjust
the slow system 1.
5 Final adjustment of intermediate system
Fine tune the intermediate system by changing the
needle type and clip position.
Air/fuel
mixture
SIZE P/NO.
Lean NECL 13383-37FG0
NEDL 13383-37FP0
NECK 13383-37FF0
NEDK 13383-37FN0
NECJ 13383-37FE0
NEDJ 13383-37FM0
NECW 13383-37FD0
NEDW 13383-37FL0
* NECH 13383-37FC0
NEDH 13383-37FK0
NECG 13383-37FB0
NEDG 13383-37FJ0
NECF 13383-37FA0
Rich NEDF 13383-37FH0
Ex. Slow jet #50
If air/fuel mixture is rich, replace it with #48
slow jet. If air/fuel mixture is lean, replace
it with #52 slow jet.
Ex. Main jet #172
If air/fuel mixture is rich, replace it with
#170 main jet. If air/fuel mixture is lean,
replace it with #175 main jet.
1/2 turn out
3/4 turn out
1 turn out
.................STD
1 and 1/4 turns out
1 and 1/2 turns out
1 and 3/4 turns out
2 turns out
Lean
STD
Rich
1
2
3
4
5