KTM 125 EXC

KTM has been offering enduro models for a long time, but it was only in 1993 that the model series was given the designation EXC (previously GS). These motorcycles are not based on the motocross model, as one might think at first glance, but were designed from the ground up for enduro use despite sharing some common components. More than just street-legal off-road machines, this model embodies the "Ready to Race" slogan in the truest sense of the word and has established itself over the years as the most powerful motorcycle in its category.

The EXC 125 underwent many changes over time. KTM often relied on innovations, e.g. with the introduction of the PDS system, a shock absorber that works without linkage and which KTM still uses in enduro racing (without linkage there is more ground clearance), a hydraulic clutch that was considered groundbreaking in the off-road sector as it was already available before the year 2000, an extremely versatile WP air suspension and finally the introduction of an injection system for two-stroke engines.

The EXC 125 disappeared from the KTM catalog after 2016. From 2017 to 2019, it was replaced by the XC-W before being completely discontinued and reappearing in 2025 with the TBI injection system from the motocross range. However, this system is not homologated by the manufacturer for the French market.

Technical data KTM EXC 125 2012 to 2016

Engine:

• Type: Single-cylinder two-stroke engine with liquid cooling and exhaust timing
• Displacement: 124.8cc
• Bore x stroke: 54 x 54.5mm
• Piston: 2-ring
• Lubrication: Premix 1:40 (two-stroke oil - JASO FD standard 100% synthetic)
• Ignition: DC CDI Kokusan
• Intake: Reed valve
• Carburetor: Keihin PWK 36S
  • Main jet: 175
  • Idle jet: 42
  • Needle: N1EG
• Clutch: Multi-plate clutch (hydraulic Brembo control)
• Starter: Kick starter
• Spark plug: NGK BR9 ECMVX
• Gearbox: 6-speed (oil 15W50 standard JASO T903 MA2)
• Gear ratio: 14/50

Maintenance: KTM recommends replacing the piston every 40 hours and changing the gear oil every 20 hours. All adjustment and maintenance information can be found in the user manual.

Note: A table with all carburetor settings depending on the conditions (temperature, altitude, mud or sand) can be found in the user manual. This manual is available on the KTM website. It is very important to follow this information to maintain the reliability and performance of your 125.

Chassis :

• Chrome-molybdenum steel tubular frame / aluminum rear frame
• Fork / Suspension travel: WP Ø48mm sprung / 300mm → Oil recommendation: SAE 5
• Shock absorber / suspension travel: WP PDS without linkage / 335mm → oil recommendation: SAE 2.5
• Front brake: Brake disk 260mm
• Rear brake: Brake disk 220mm
• Dry weight: 95 kg
• Seat height: 960mm
• Front tire: 80/100-21
• Rear tire: 120/90-18
• Fuel tank: 9.5L (unleaded 95 recommended)

Maintenance: KTM recommends changing the fork and shock absorber oil every 40 operating hours. All adjustment and maintenance information can be found in the owner's manual.

KTM EXC 125 In our online store

In our online store, we strive to offer you high-quality parts with fast delivery times and at the best price. You will find chain sets, fork seals and oil for ongoing maintenance for your 125 SX, as well as custom parts for individual design: plastic kits, handlebars, grips, levers, etc.