KTM 125 SX Specs

2017 - 2023 • 6 variants

KTM has built the 125 SX, an enduro motorcycle, across 6 variants since 2017, most recently updated for 2023. Under the tank sits a reed intake., 124.8 cc in capacity. Torque tops out at 9.2 Nm.

About the KTM 125 SX

As a Cross / motocross motorcycle, the KTM 125 SX was offered from the 2003 through to the 2023 model year. The technical data presented here covers the complete specification range for this model, including all engine variants, chassis dimensions, suspension travel, brake specifications, and weight figures. This information is useful for prospective buyers, current owners, and mechanics working on the KTM 125 SX.

KTM 125 SX by Year

2023 KTM 125 SX View specs →

2022 KTM 125 SX View specs →

2020 KTM 125 SX View specs →

2019 KTM 125 SX View specs →

2018 KTM 125 SX View specs →

2017 KTM 125 SX View specs →

Spec Evolution

How key specs changed across production years.

Specification	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	2020	2021	2022	2023
Stroke	2	2	2	2	2	2	2	-	-	-	-	-	-	-	-	-	-	-	-	-	2-stroke
Seat Heigth -Alternate (mm)	-	675 mm	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Seat Heigth -Alternate (in.)	-	26.6 inches	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Ground Clearance (mm)	390 mm	390 mm	390 mm	390 mm	390 mm	390 mm	390 mm	390 mm	385 mm ↓	395 mm ↑	395 mm	395 mm	395 mm	375 mm ↓	375 mm	375 mm	375 mm	-	375 mm	375 mm	359 mm ↓
Ground Clearance (in.)	15.4 inches	15.4 inches	15.4 inches	15.4 inches	15.4 inches	15.4 inches	15.4 inches	15.4 inches	15.2 inches ↓	15.6 inches ↑	15.6 inches	15.6 inches	15.6 inches	14.8 inches ↓	14.8 inches	14.8 inches	14.8 inches	-	14.8 inches	14.8 inches	14.1 inches ↓
Fuel Control	-	-	-	-	-	-	-	-	Single Overhead Cams (SOHC)	Single Overhead Cams (SOHC)	Single Overhead Cams (SOHC)	-	-	-	-	-	-	Double Overhead Cams/Twin Cam (DOHC)	Double Overhead Cams/Twin Cam (DOHC)	-
Engine Type	Single cylinder	Single cylinder	Single cylinder	Single cylinder	Single cylinder	Single cylinder	Single cylinder	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke
Displacement (cc)	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.80 cc	124.8 cc	124.8 cc	124.8 cc	124.8 cc	124.8 cc
Comments	-	-	-	-	-	-	-	-	With reverse. German brand.	-	-	German brand.	-	-	-	-	-	-	-	-
Brakes - Rear Diameter (mm)	220 mm	260 mm ↑	260 mm	220 mm ↓	-	220 mm	220 mm	220 mm	220 mm	220 mm	210 mm ↓	220 mm ↑	220 mm	220 mm	220 mm	220 mm	-	-	-	-
Brakes - Rear Diameter (in.)	8.7 inches	10.2 inches ↑	10.2 inches	8.7 inches ↓	-	8.7 inches	8.7 inches	8.7 inches	8.7 inches	8.7 inches	8.3 inches ↓	8.7 inches ↑	8.7 inches	8.7 inches	8.7 inches	8.7 inches	-	-	-	-
Brakes - Front Diameter (mm)	260 mm	216 mm ↓	216 mm	260 mm ↑	-	260 mm	260 mm	260 mm	260 mm	260 mm	220 mm ↓	260 mm ↑	260 mm	260 mm	260 mm	260 mm	-	-	-	-
Brakes - Front Diameter (in.)	10.2 inches	8.5 inches ↓	8.5 inches	10.2 inches ↑	-	10.2 inches	10.2 inches	10.2 inches	10.2 inches	10.2 inches	8.7 inches ↓	10.2 inches ↑	10.2 inches	10.2 inches	10.2 inches	10.2 inches	-	-	-	-
Bore x Stroke (mm)	45.0 x 40.8 mm	54.0 x 54.5 mm ↑	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm	54.0 x 54.5 mm
Bore x Stroke (in,)	1.8 x 1.6 inches	2.1 x 2.1 inches ↑	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches	2.1 x 2.1 inches
Seat Height	925 mm / 36.4 in.	925 mm / 36.4 in.	925 mm / 36.4 in.	925 mm / 36.4 in.	925 mm / 36.4 in.	960 mm / 37.8 in. ↑	985 mm / 38.8 in. ↑	985 mm / 38.8 in.	992 mm / 39.1 in. ↑	992 mm / 39.1 in.	992 mm / 39.1 in.	992 mm / 39.1 in.	992 mm / 39.1 in.	960 mm / 37.8 in. ↓	960 mm / 37.8 in.	960 mm / 37.8 in.	950 mm / 37.4 in. ↓	-	850 mm / 33.5 in.	950 mm / 37.4 in. ↑	958 mm / 37.7 in. ↑
Dry Weight	93.6 kg / 206.4 lbs	93.6 kg / 206.4 lbs	92.4 kg / 203.7 lbs ↓	92.4 kg / 203.7 lbs	92.4 kg / 203.7 lbs	90.8 kg / 200.2 lbs ↓	90.8 kg / 200.2 lbs	90.8 kg / 200.2 lbs	88.8 kg / 195.8 lbs ↓	91.6 kg / 201.9 lbs ↑	90.8 kg / 200.2 lbs ↓	90.8 kg / 200.2 lbs	90.8 kg / 200.2 lbs	87.8 kg / 193.6 lbs ↓	87.2 kg / 192.2 lbs ↓	87.2 kg / 192.2 lbs	87.5 kg / 192.9 lbs ↑	137 kg / 302.0 lbs ↑	87.5 kg / 192.9 lbs ↓	87.5 kg / 192.9 lbs	92.4 kg / 203.7 lbs ↑
Frame Type	-	Chromium molybdenum	Chromium molybdenum	Central double-cradle-type 25 CrMo4	Central double-cradle-type 25CrMo4	Central double-cradle-type 25CrMo4	Central double-cradle-type 25CrMo4	Central double-cradle-type 25CrMo4	Central double-cradle-type 25CrMo4. Subframe: Aluminium.	Central tube frame made of chrome molybdenum steel tubing	Central tube frame made of chrome molybdenum steel tubing	Central tube frame made of chrome molybdenum steel tubing	Central tube frame made of chrome molybdenum steel tubing	Chrome-molybdenum steel central-tube frame	Chrome-molybdenum steel central-tube frame	Chrome-molybdenum steel central-tube frame	Chrome-molybdenum steel central-tube frame	Central double-cradle	Central double-cradle-type 25CrMo4 steel	Central double-cradle-type 25CrMo4 steel	Central double-cradle-type 25CrMo4 steel
Engine Detail	-	-	-	-	-	-	-	-	-	Reed intake and exhaust control	Reed intake.	Reed intake.	Reed intake.	Reed intake.	Reed intake.	Reed intake.	Reed intake.	-	-	-
Brakes - Front	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc. Four-piston calipers.	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc	Single disc	Single disc	Single disc
Wheelbase	1,461 mm / 57.5 in.	1,471 mm / 57.9 in. ↑	1,471 mm / 57.9 in.	1,471 mm / 57.9 in.	1,417 mm / 55.8 in. ↓	1,471 mm / 57.9 in. ↑	1,471 mm / 57.9 in.	1,471 mm / 57.9 in.	1,480 mm / 58.3 in.	1,480 mm / 58.3 in.	1,480 mm / 58.3 in.	1,480 mm / 58.3 in.	1,480 mm / 58.3 in.	1,485 mm / 58.5 in.	1,485 mm / 58.5 in.	1,485 mm / 58.5 in.	1485 mm / 58.5 in. ↑	-	-	-	-
Fuel Capacity	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	8.00 litres / 2.11 gallons ↑	8.00 litres / 2.11 gallons	7.50 litres / 1.98 gallons ↓	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.00 litres / 1.85 gallons ↓	7.00 litres / 1.85 gallons	7.00 litres / 1.85 gallons	7.50 litres / 1.98 US gallons ↑	-	7.50 litres / 1.98 US gallons	7.50 litres / 1.98 US gallons	7.20 litres / 1.90 US gallons ↓
Brakes - Rear	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc	Single disc. Two-piston calipers.	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc. Brake calipers on floating bearings	Single disc	Single disc	Single disc	Single disc
Suspension - Front	-	WP-USD 48/26 MA/PA	WP-USD 48 mm (1.89 inch.)	WP-USD 48 mm (1.89 inches)	WP USD, 43 mm ↓	WP USD 43 mm (1.69	WP USD, 43 mm	WP USD, 43 mm	WP USD 48 mm (1.89 in) ↑	WPSuspension	WP ?Suspension Up Side Down 4860 MXMA CC	WP ?Suspension Up Side Down 4860 MXMA CC	WP ?Suspension Up Side Down 4860 MXMA CC	WP-USD, AER 48, ? 48 mm ↓	WP-USD, AER 48, ? 48 mm	WP-USD, AER 48, ? 48 mm	WP-USD, AER 48, Ø 48 mm	WP upside-down Ø 48 mm	WP XACT-USD, Ø 48 mm	WP XACT-USD, Ø 48 mm	WP XACT-USD, Ø 48 mm
Suspension - Rear	-	WP-PDS-DA shock absorber	WP-PDS-DA shock absorber	WP-PDS shock absorber	WP monoshock PDS	WP monoshock PDS	WP PDS shock absorber	WP PDS shock absorber	WP PDS shock absorber	WPSuspension	WP ?Suspension 5018 BAVP DCC	WP ?Suspension 5018 BAVP DCC	WP ?Suspension 5018 BAVP DCC	WP shock absorber with linkage	WP shock absorber with linkage	WP shock absorber with linkage	WP shock absorber with linkage	WP Monoshock	WP XACT Monoshock with linkage	WP XACT Monoshock with linkage	WP XACT Monoshock with linkage
Fuel System	Carburettor	Carburettor	Carburettor. Keihin PWK 39	Carburettor. Keihin PWK 39	Carburettor. Keihin PWK 39	Carburettor. Keihin PWK 39	Carburettor. Keihin PWK 39	Carburettor. Keihin PWK 39	Carburettor. Keihin PWK 38S AG ↓	Carburettor. Keihin PWK 38S AG	Carburettor	Carburettor	Carburettor	Carburettor	Carburettor. Mikuni TMX	Carburettor. Mikuni TMX	Carburettor. Mikuni TMX	Injection	Injection	Injection	Injection
Colours	-	Orange	-	-	-	-	Orange/black	Orange	Orange/black/white	Orange/black/white	Orange/black	Orange/black	Orange/black	Orange/white/black	Orange/white/black	Orange/white/black	Orange/white/black	White, Orange	White/Orange	White/orange/blue	White/orange/grey
Clutch	-	-	Wet multi-disc clutch, operated hydraulically	Wet multi-disc clutch, operated hydraulically	Wet multi-disc clutch, operated hydraulically	Wet multi-disc clutch, operated hydraulically	Wet multi-disc clutch, operated hydraulically	Wet multi-disc clutch, operated hydraulically	Wet mDouble disk clutch, operated hydraulically	Wet mDouble disk clutch / hydraulically operated	Wet multi-disc clutch / hydraulically operated	Wet multi-disc clutch / hydraulically operated	Wet multi-disc clutch, hydraulically operated	Multi-plate clutch, Brembo hydraulics	Multi-plate clutch, Brembo hydraulics	Multi-plate clutch, Brembo hydraulics	Wet multi-disc clutch, hydraulically actuated	Wet multi-disc clutch, mechanically actuated	Multi-plate clutch, Brembo hydraulics	Multi-plate clutch, Brembo hydraulics	Wet multi-disc DS clutch, Brembo hydraulics
Final Drive	Chain	Chain	Chain	-	Chain	-	-	-	Chain	Chain	Chain	Chain	Chain	Chain	Chain	Chain	Chain (final drive)	Chain (final drive)	Chain (final drive)	Chain (final drive)	Chain (final drive)
Rims	-	-	-	-	-	-	-	-	1.60 x 21in., 2.15 x 19in. Excel	-	-	-	-	-	CNC machined hubs. Excel rims. Wire spoked.	CNC machined hubs. Excel rims. Wire spoked.	CNC machined hubs. Excel rims. Wire spoked.	-	-	-
Height	-	-	-	-	-	-	-	-	-	1,146 mm / 45.1 in.	1,140 mm / 44.9 in.	1,120 mm / 44.1 in. ↓	-	-	-	-	-	-	-	-	-
Length	-	-	-	-	-	-	-	-	1,400 mm / 55.1 in.	2,065 mm / 81.3 in. ↑	2,090 mm / 82.3 in. ↑	2,120 mm / 83.5 in. ↑	-	-	-	-	-	-	-	-	-
Compression Ratio	-	-	-	-	-	-	-	-	-	8.3:1	10.6:1 ↑	-	-	-	-	-	-	-	-	-
Warranty	-	-	-	-	-	-	-	-	-	12 Months	-	-	-	-	-	-	-	-	-	-
Wet Weight	-	-	-	-	-	-	-	-	104.0 kg / 229.3 lbs	292.1 kg / 643.9 lbs ↑	-	112.0 kg / 246.9 lbs	-	-	-	-	-	-	-	-	-
Emissions	-	-	-	-	-	-	-	-	Euro 2	-	-	Euro 2	-	-	-	-	-	-	-	-
Engine Lubrication	-	-	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	Mixture oil lubrication 1:40	-	-	-	-	-	-	-	Wet sump	Wet sump	Wet sump	Wet sump
Tyres - Front	80/100-21	-	-	80/100-21	80/100-21	80/100-21	80/100-21	80/100-21	19/7-8 ↓	80/100-21 ↑	100/80-17 ↑	110/70-17 ↑	-	-	-	-	-	110-17	110-17	110-17	1.6-21 ↓
Gearbox	5-speed	5-speed	5-speed	6-speed ↑	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed	6-speed
Width	-	-	-	-	-	-	-	-	960 mm / 37.8 in.	1,204 mm / 47.4 in. ↓	830 mm / 32.7 in. ↑	840 mm / 33.1 in. ↑	-	-	-	-	-	-	-	-	-
Tyres - Rear	100/90-19	-	-	100/90-19	100/90-19	100/90-19	100/90-19	100/90-19	100/90-19	100/90-19	110/80-17 ↑	130/70-17 ↑	-	-	-	-	-	-	-	-
Primary Drive	-	-	-	-	-	-	-	-	13:50. Primary drive: 23:73.	13:50	13:50. Primary drive: 23:73.	13:50. Primary drive: 23:73.	13:50. Primary drive: 23:73.	13:50. Primary drive: 23:73.	13:50. Primary drive: 23:73.	13:50. Primary drive: 23:73.	13:50. Primary drive: 23:73.	5/8 x 1/4 (520) O Ring. Primary drive: 22:72. ↓	5/8 x 1/4 (520) O Ring. Primary drive: 22:72.	5/8 x 1/4 (520) O Ring. Primary drive: 22:72.	X-Ring 5/8 x 1/4´ chain
Rake	-	24.0°	27.0° ↑	27.0°	27.0°	27.0°	27.0°	27.0°	26.5° ↓	26.5°	26.5°	26.5°	26.5°	26.5°	26.5°	26.5°	26.1° ↓	-	26.1°	26.1°	26.1°
Exhaust	-	-	-	Aluminum	Aluminium	Aluminium	Aluminium	Aluminium	Aluminium	-	-	Stainless steel exhaust	-	-	-	-	-	-	-	-
Instrumentation	-	-	-	-	-	-	-	-	-	-	-	Digital cockpit	-	-	-	-	-	-	-	-
Lighting system	-	-	-	-	-	-	-	-	-	30W x 2 halogen	-	-	-	-	-	-	-	-	-	-
Trail	-	63 mm / 2.5 in.	120 mm / 4.7 in. ↑	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Wheel Travel - Front	300 mm / 11.8 in.	-	300 mm / 11.8 in.	300 mm / 11.8 in.	115 mm / 4.5 in. ↓	300 mm / 11.8 in. ↑	300 mm / 11.8 in.	300 mm / 11.8 in.	185 mm / 7.3 in. ↓	300 mm / 11.8 in. ↑	205 mm / 8.1 in. ↓	300 mm / 11.8 in. ↑	300 mm / 11.8 in.	300 mm / 11.8 in.	300 mm / 11.8 in.	300 mm / 11.8 in.	310 mm / 12.2 in. ↑	-	310 mm / 12.2 in.	310 mm / 12.2 in.	310 mm / 12.2 in.
Wheel Travel - Rear	335 mm / 13.2 in.	-	335 mm / 13.2 in.	335 mm / 13.2 in.	185 mm / 7.3 in. ↓	335 mm / 13.2 in. ↑	335 mm / 13.2 in.	335 mm / 13.2 in.	185 mm / 7.3 in. ↓	330 mm / 13.0 in. ↑	185 mm / 7.3 in. ↓	317 mm / 12.5 in. ↑	317 mm / 12.5 in.	300 mm / 11.8 in. ↓	300 mm / 11.8 in.	300 mm / 11.8 in.	300 mm / 11.8 in.	150 mm / 5.9 in. ↓	300 mm / 11.8 in. ↑	300 mm / 11.8 in.	300 mm / 11.8 in.
Ignition	-	-	Kokusan digital 2K-1	Kokusan digital 2K-1	Kokusan digital 2K-1	Kokusan digital magneto CDI	Kokusan	Kokusan	Kokusan	Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan	Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan	Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan	Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan	Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan	Kokusan EMS	Kokusan EMS	Kokusan EMS	Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan	Kokusan EMS	Kokusan EMS	Vitesco Technologies EMS
Max Torque	-	-	-	-	-	-	-	-	-	-	9.20 Nm (0.9 kgf-m or 6.8 ft.lbs) @ 7000 Revolutions	-	-	-	-	-	-	-	-	-
Power-to-Weight Ratio	-	-	-	-	-	-	-	-	-	-	0.0815 HP/kg	-	-	-	-	-	-	0.1095 HP/kg	0.1714 HP/kg ↑	0.1714 HP/kg	0.1623 HP/kg
Starter	-	-	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Kick	Electric	Kick	Kick	Electric
Valve System	-	-	-	-	-	-	-	-	-	-	2	-	-	-	-	-	-	-	-	-

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