KTM 125 SX 2021 User Manual

TECHNICAL DATA 21
135
Idling jet 37.5
Jet needle 6BFY42‑71
Needle position 3rd position from top
Main jet 580
Info
If the engine is not running smoothly, use a smaller main jet.
21.4 Capacities
21.4.1 Gear oil
Gear oil 0.80 l (0.85 qt.) Engine oil (15W/50) ( p. 141)
21.4.2 Coolant
Coolant 1.2 l (1.3 qt.) Coolant ( p. 141)
21.4.3 Fuel
Total fuel tank capacity, approx.
(All SX models)
7.5 l (1.98 US gal) Super unleaded (98 octane) mixed
with 2-stroke engine oil (1:40)
( p. 142)
Total fuel tank capacity, approx.
(125 XC US)
10 l (2.6 US gal) Super unleaded (98 octane) mixed
with 2-stroke engine oil (1:40)
( p. 142)
21.5 Chassis
Frame Central tube frame made of chrome molybdenum steel
tubing
Fork WP XACT 5448
Shock absorber WP XACT 5750
Suspension travel
front 310 mm (12.2 in)
rear 300 mm (11.81 in)
Fork offset 22 mm (0.87 in)
Brake system Disc brakes, floating brake calipers
Brake discs - diameter
front 260 mm (10.24 in)
rear 220 mm (8.66 in)
Brake discs - wear limit
front 2.5 mm (0.098 in)
rear 3.5 mm (0.138 in)
Offroad tire pressure
front 1.0 bar (15 psi)
rear 1.0 bar (15 psi)
Secondary ratio (All 125 models) 13:51
Secondary ratio (150 SX) 13:48

KTM 125 SX 2021 Specifications

General

Engine Type	1-cylinder, 2-stroke engine
Displacement	124.8 cm³
Bore x Stroke	54 mm x 54.5 mm
Starter	Kickstarter
Transmission	6-speed
Front Suspension	WP XACT-USD, Ø 48 mm
Rear Suspension	WP XACT Monoshock with linkage
Cooling	Liquid cooled
Front Tire	80/100-21"
Rear Tire	100/90-19"
Seat Height	950 mm
Ground Clearance	375 mm
Frame	Central tube frame made of chrome molybdenum steel
Front Brake	Disc brake
Rear Brake	Disc brake
Fuel Tank Capacity	7.5 liters
Fuel System	Mikuni TMX carburetor