KTM 50 SX JUNIOR - Manual (Page 36)

TECHNICAL DATA – ENGINE
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ENGINE 50 SX JUNIOR 50 SX
Design single cylinder 2-stroke engine, with reed valve inlet
Displacement 49.0 cc
Bore/Stroke 39.5 / 40 mm
Fuel SUPER fuel, research octane no 95, mixed with 2-stroke oil
Oil/gasoline ratio 1 : 60 when using high grade 2-stroke oil (Motorex 2T Cross Power) When in doubt,
please contact your importer
Lubrication mixture lubrication
Crankshaft bearing 2 grooved ball bearing
Connecting rod bearing needle bearing
Piston pin bearing needle bearing
Piston rings 1 rectangular ring
Primary drive straight cut spur gears, 16 : 57 Z
Transmission oil 0.15-0,2 liter automatic gear oil Dexron II (Motorex Topspeed 4T 15W50)
Spark plug NGK BR 8 ECM
Electrode gap 0.6 mm
Carburetor Dell’Orto PHVA 14 DS Dell’Orto PHBG 19 BS
Air filter wet foam type air filter insert
Cooling liquid 0.5 litres, 50% antifreeze, 50% distilled water, at least -25 °C (-13 °F)
BASIC CARBURETOR SETTING
Model
50 SX Junior 50 SX
Type Dell’Orto PHVA 14 DS Dell’Orto PHBG 19 BS
Main jet 80 85
Needle jet 211 FA 260 AU
Idling jet 45 48
Jet needle A10 W9
Needle position from top 3. 3.
Air/Mixture reg. screw open 3.5 3.0
Slide 40 60
Starting jet 60 60
TIGHTENING TORQUES - ENGINE
Primary gear nut
M14x1,25 40 Nm
Hexagon nut ignition rotor M10x1,25 20 Nm
Nut of clutch hub M10x1,25 Loctite 243 + 35 Nm
Cylinder head screws M7 15 Nm
Cylinder base nuts M8 18 Nm
Allan head screw-Stator M5x25 Loctite 243 + 8 Nm
Oil plug M16 5 Nm
Oil drain plug M10 15 Nm
Other engine screws M5 7 Nm
M6 10 Nm
M8 30 Nm