KTM 50 SX 2017, Owner'S Manual

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20 TECHNICAL DATA
88
20.1 Engine
Design 1-cylinder 2-stroke engine, water-cooled, with reed intake
Displacement 49.0 cm³ (2.99 cu in)
Stroke 40 mm (1.57 in)
Bore 39.5 mm (1.555 in)
Crankshaft bearing 2 grooved ball bearings
Conrod bearing Needle bearing
Piston pin bearing Needle bearing
Pistons Aluminum cast
Piston rings 1 rectangular ring
Engine lubrication (50 SX) Mixture oil lubrication
Engine lubrication (50 SX Mini) Separate lubrication
Primary transmission 33:61 straight cut spur gear
Clutch Multi-disc automatic clutch on the main shaft/centrifugal force
Gearbox Rigid 1-stage reduction gear
Transmission ratio 14:31
Ignition SELETTRA 2p D36
Spark plug NGK LR 8 B
Spark plug electrode gap 0.60 mm (0.0236 in)
Cooling Water-cooled
Starting aid Kickstarter
20.2 Engine tightening torques
Screw, bearing retainer M5 5 Nm (3.7 lbf ft)
–
Screw, kickstarter M5 6 Nm (4.4 lbf ft) Loctite ® 243™
Screw, oil pump (50 SX Mini) M5 6 Nm (4.4 lbf ft)
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Screw, stator clamp M5 6 Nm (4.4 lbf ft) Loctite ® 222™
Screw, water pump wheel M5 5 Nm (3.7 lbf ft) Loctite ® 243™
Bleeder flange of engine case M6 4 Nm (3 lbf ft) Loctite ® 243™
Drain plug, water pump cover M6 6 Nm (4.4 lbf ft)
–
Screw, alternator cover M6 6 Nm (4.4 lbf ft)
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Screw, clutch cover M6 10 Nm (7.4 lbf ft)
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Screw, engine case M6 10 Nm (7.4 lbf ft)
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Screw, engine sprocket cover M6 10 Nm (7.4 lbf ft)
–
Screw, exhaust flange M6 10 Nm (7.4 lbf ft) Loctite ® 243™
Screw, fitting pin M6 10 Nm (7.4 lbf ft) Loctite ® 648™
Screw, gear oil level check M6 6 Nm (4.4 lbf ft)
–
Screw, ignition coil M6 4 Nm (3 lbf ft) Loctite ® 243™
Screw, intake flange M6 5 Nm (3.7 lbf ft) Loctite ® 243™
Screw, pressure plate M6 10 Nm (7.4 lbf ft)
Loctite ® 243™
Screw, water pump cover M6 10 Nm (7.4 lbf ft)
–
Screw, cylinder head M7 18 Nm (13.3 lbf ft)
–
Nuts, cylinder base M8 20 Nm (14.8 lbf ft)
–
Screw, outer clutch hub M8 35 Nm (25.8 lbf ft) Loctite ® 243™
Stud bolt, cylinder base M8 10 Nm (7.4 lbf ft)
–
Spark plug M10x1 10… 12 Nm (7.4…
8.9 lbf ft)
–
Nut, primary gear M10x1.25 40 Nm (29.5 lbf ft) Loctite ® 243™
Nut, rotor M10x1.25 15 Nm (11.1 lbf ft) Loctite ® 243™
Oil drain plug with magnet M12x1.5 20 Nm (14.8 lbf ft)
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