1
2
8-2
Art.- No. 3.206.088-E
main jet
jet needle
jet needle
air control screw
idle adjusting screw
idle jet
throttle valve
Repair manual KTM 250 / 300
Idling range
A
Operation with closed throttle valve. This range is influenced by the position of the air control screw
1
and the idle adjusting
screw
2
. Only make adjustments when the engine is hot.
To adjust, slightly increase the idling speed of the engine by means of the idle adjusting screw. Turning it clockwise produces a
higher idling speed and turning the screw counterclockwise produces a lower idling speed. Create a round and stable engine
speed using the air control screw (basic position of the air control screw = open by 1.0 turns). Then adjust to the normal idling
speed by means of the idle adjusting screw.
NOTE: The engine braking effect will be lost of the idling speed is too high.
Opening up
B
Engine behavior when the throttle opens. The idle jet and the shape of the throttle valve influences this range. If, despite good
idling-speed and part-throttle setting, the engine sputters and smokes when the throttle is fully opened and develops its full
power not smoothly but suddenly at high engine speeds, the mixture to the carburetor will be too rich, the fuel level too high or
the float needle is leaking.
Part-throttle range
C
Operation with partly open throttle valve. This range is only influenced by the jet needle (shape and position). The optimum part-
throttle setting is controlled by the idling setting in the lower range and by the main jet in the upper range. If the engine runs on
a four-stroke cycle or with reduced power when it is accelerated with the throttle partly open, the jet needle must be lowered by
one notch. If then the engine pings, especially when accelerating under full power at maximum engine revs, the jet needle
should be raised.
If these faults should occur at the lower end of the part throttle range at a four-stroke running, make the idling range leaner; if
the engine pings, adjust the idling range richer.
Full throttle range
D
Operation with the throttle fully open (flat out). This range is influenced by the main jet and the jet needle. If the porcelain of
the new spark plug is found to have a very bright or white coating or if the engine rings, after a short distance of riding flat out, a
larger main jet is required. If the porcelain is dark brown or black with soot the main jet must be replaced by a smaller one.
mixture too rich:
too much fuel in proportion to air
mixture too lean:
not enough fuel in proportion to air
OPERATING RANGES OF THE CARBURETOR
Summary of Contents for 125 SX 2010
Page 2: ...OWNERSMANUAL2010 250 SX 250 300 XC XC W EXC EXC SixDays ...
Page 3: ...OWNER S MANUAL 2010 125 SX 150 SX 250 SX Art no 3211480en ...
Page 91: ...TECHNICAL DATA SHOCK ABSORBER 89 Shock absorber oil p 95 SAE 2 5 ...
Page 93: ...91 ...
Page 222: ...119 ...
Page 223: ...WIRING DIAGRAM 120 ...
Page 226: ...WIRING DIAGRAM 123 ...
Page 304: ...1 2 3 4 7 12 Art No 3 206 088 E Repair manual KTM 250 300 ...
Page 306: ...bl bk 6 7 8 9 7 14 Art No 3 206 088 E Repair manual KTM 250 300 ...
Page 308: ...1 2 3 4 5 7 16 Art No 3 206 088 E Repair manual KTM 250 300 ...
Page 393: ...11 15 PERIODIC MAINTENANCE SCHEDULE 2010 250 SX ...
Page 394: ...11 16 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 396: ...11 18 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 397: ...11 19 ...
Page 409: ...EXC 250 300 2005 EXC SIX DAYS 250 300 05 06 12 11 ...
Page 413: ...EXC 250 300 2005 EXC SIX DAYS 250 300 05 06 12 15 ...
Page 414: ...EXC USA 250 2005 12 16 Art No 3 206 088 E Repair manual KTM 250 300 ...
Page 416: ...12 18 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 430: ...Repair manual KTM 250 300 Art No 3 206 088 E 12 32 250 EXC EXC Six Days EU AUS 2008 2009 ...
Page 431: ...12 33 250 300 XC USA 2008 250 CX W ZA 2008 2009 ...
Page 433: ...12 35 300 EXC E EXC E SixDays EU AUS 2008 2009 ...
Page 437: ...12 39 250 SX 2010 ...
Page 438: ...12 40 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 439: ...12 41 250 EXC EU 2010 ...
Page 440: ...12 42 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 441: ...12 43 250 300 EXC 2010 ...
Page 442: ...12 44 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 443: ...12 45 250 300 XC XC W 2010 ...
Page 444: ...12 46 Repair manual KTM 250 300 Art No 3 206 088 E ...
Page 445: ...REPAIRMANUAL2004 2010 2004 2005 DCC ...
Page 553: ...1 7 T 14031 Dismounting mounting tool ...
Page 559: ...2 6 Exploded view PDS 5018 SXS SMR 2005 2006 ...
Page 561: ...2 8 Exploded view PDS 5018 SXS 2007 ...
Page 739: ...1 7 T 14 030 Adaptor T 14 033 Assembling tool ...
Page 741: ...2 2 Repair manual WP Fork Closed Cartridge Art No 3 211 199 E Exploded view SXS 2005 ...
Page 746: ...2 7 Exploded view SXS 2006 ...
Page 751: ...2 12 Repair manual WP Fork Closed Cartridge Art No 3 211 199 E Exploded view SX 2007 ...
Page 756: ...2 17 Exploded view Fork SXS 2007 ...