KTM 250 SX - Manual (Page 85)

Repair manual KTM 250 / 300 / 380
Art No 3206004 -E
9-2C
Engine
250 SX
250 EXC, MXC
300 EXC, MXC
380 SX
380 EXC, MXC
Design
Liquid-cooled single-cylinder two-str
oke engine with
KTM T
win
V
alve
C
ontr
ol exhaust system and
K
TM
T
or
que
C
hamber
Piston displacement
249 ccm
297 ccm
368 ccm
Bor
e / str
oke
67.5 / 69.5 mm (2.66 / 2.74 in)
72 / 73 mm (2.84 / 2.88 in)
78 / 77 mm (3 / 2.98 in)
Fuel
SUPER fuel, r
esear
ch octane no 95, mixed with high-grade two str
oke oil (Shell Advance Racing X)
Oil / gasolin ratio
1:50 - 1:60 when using high grade two str
oke oil. When in doupt, please contact your importer or use 1:40 mi
x ratio to be on the safe side
Crankshaft bearing
1 deep-gr
oove ball bearing / 1 cylinder r
oller bearing
Connecting r
od bearing
needle bearing
Piston pin bearing
needle bearing
Piston
cast piston
for
ged piston
cast piston
Piston ring
two plain compr
ession rings
Dimension "X"
0 mm
+0.1 mm
(0 in
+ 0.004 in
)
Ignition timing
1.8 mm (0.07 in) (17 °) BTDC
2.0 mm (0.08 in) (17°) BTDC
2.2 mm (0.09 in) (17 °) BTDC
Spark plug
NGK
BR
8 ECM
Electr
ode gap
0.6 mm (0.024 in)
Dimension "Z"
48 mm (1.9 in)
46 mm (1.7 in)
50.5 mm (1.99 in)
TVC start open
5400/min
5300/min
5200/min
TVC fully open
7550/min
7750/min
7200/min
Primary drive
straight cut spur gears, primary ratio 25:72
straight cut spur gears, primary ratio 26:72
Clutch
multiple disc clutch in oil bath, hydraulic operated (Shell HF-E15)
Transmission
5 speed, claw actuated
Gear ratio
EXC
M-XC
EXC
MXC
1 st
Gear
15:29
15:29
15:29
15:29
15:29
15:29
15:29
2 nd
Gear
17:27
18:26
18:26
18:26
18:26
18:26
18:26
3 rd
Gear
19.25
19:22
19:22
19:24
19:24
19:22
19:24
4 th
Gear
21:23
21:20
21:20
21:23
21:23
21:20
21:23
5 th
Gear
23:21
23:18
23:18
23:21
23:21
23:18
23:21
Gear lubrication
0.8 l engine oil 20W
-40 (Shell Advance VSX4)
A
vailable chain spr
ockets
13t / 14t / 15t for chain
5
/ 8
x
1
/ 4
"
Coolant
1.3 litr
es, 40% anti fr
eeze, 60% water
, at least -25 °C (-13 °F)
Ignition system
KOKUSAN 2K-1
KOKUSAN 2K-2
KOKUSAN 2K-1
KOKUSAN 2K-2
Generator output
no generator
12V 40W
no generator
12V 40W
Carbur
etor
flat-slide carbur
etor
, carbur
etor setting see table 3
Air
-filter
wet foam type air filter insert
(upper edge piston - upper edge cylinder) (height of the contr
ol flap)
TECHNICAL SPECIFICA
TIONS - ENGINE 250/300/380 SX/MXC/EXC ‘99 (only for USA)