3. Adjustments
USE AND MAINTENANCE MANUAL
CHAPTER 3
ADJUSTMENTS
2-Strokes - Edition 01 / 2023
91
3
1
1
1
XX 125 / XX 250
1
Adjusting the main jet
The richness of air-fuel mixture with 1/2–4/4 throttle can be
set by changing the main jet “1”.
Standard main jet
XX 125 version: #162
XE 125 “Racing” version: #162
XE 125 approved version: #105
XX 250 : #190
– Spark plug is too hot: select a main jet having higher
calibrating No. than standard. (To be enriched);
– Spark plug is wet: select a main jet having lower calibrating
No. than standard. (To be leaned out).
Adjusting the Power Jet (XX 125 / XX 250 versions)
The richness of the air-fuel mixture with flow control valve
1/2 to 4/4, below 8500 rpm, can be set by changing the power
jet “1”. A larger jet size produces a richer mixture, while a
smaller size produces a leaner mixture
Standard Power Jet
XX 125 version : #35
XX 250 version : #50
Adjusting the pilot air screw
The air-fuel mixture ratio can be adjusted by turning the air
pilot screw “1”: with the flow control valve from fully closed
to 1/8.
Screwing in the air pilot screw will enrich the mixture at low
revs and unscrewing it will make the mixture leaner.
Standard pilot air screw position:
1–3/4 turns outwards (XX 125 version)
1–1/2 turns outwards (XE 125 version)
2–1/4 turns outwards (XX 250 version)
Adjusting the pilot jet
The richness of the air-fuel mixture with the flow control
valve from fully closed to 1/2 can be set by changing the idle
jet “1”. Jet “1” must be replaced when the adjustment cannot
be made by adjusting the IDLE AIR SCREW.
Standard pilot jet:
XX 125 version: #62
XE 125 “Racing” version: #60
XE 125 approved version: #35
XX 250 : #55
