KTM 125 Duke 2011–2012: Specs, Facts & Known Issues

The Machine's Character

The 2011–2012 KTM 125 Duke is the rare small bike that doesn't feel like something you're supposed to outgrow in a season. It has a steel trellis frame, an upside-down WP fork and Bybre brakes. That is hardware you would normally expect a class or two higher, and the sharp orange styling has the same attitude as the bigger Dukes. The liquid-cooled 125 cc single makes 15 hp at 10,500 rpm and 9 lb-ft at 8,000 rpm. Those are modest numbers. In a 282 lb (128 kg) package they're enough to let the chassis do the talking, and the chassis is the whole story here.

It rides like a proper KTM in miniature. It's light and direct, easy to place, and cheap to run day to day. A new rider gets a machine that builds good habits in traffic and on a tight back road, and a more experienced rider gets a reminder of how much fun momentum can be. There are two honest caveats. A 78 mph (125 km/h) top speed rules out serious freeway duty. Ownership isn't carefree either: seized gear selectors, erratic fueling, dash faults, coolant and oil leaks, and chains and sprockets worn out by 2,500 miles are all documented. Buy one with a clean dealer history.

Hard Numbers

Spec sheets don't ride bikes, but they set the baseline.

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Key specifications
Power	15 hp (11 kW) @ 10,500 rpm
Torque	9 lb-ft (12 Nm) @ 8,000 rpm
Displacement	125 cc
Engine	Single-cylinder
Cooling	Liquid-cooled
Gearbox	6-speed
Final drive	Chain
Fork	Upside-down (USD)
Front tire	110/70-17
Rear tire	150/60-17
Seat height	31.9 in (810 mm)
Wet weight	282 lb (128 kg)
Fuel capacity	2.9 gal (11 L)
Top speed	78 mph (125 km/h)

Equipment check

Chassis

Rear Suspension Adjustable Standard

Known issues

Seized gear selector

drivetrain rare

The gear selector may seize, making gear changes difficult or impossible; requires dealer intervention.
Engine spluttering and mapping issues

fuel system rare

Engine may splutter or run erratically, possibly due to ECU mapping faults; can cause poor performance.
Dashboard and speedometer malfunction

electrics occasional

Dashboard may flicker, mist up, or display incorrect service reminders; speedometer can also fail intermittently.
Brake light switch failure

brakes occasional

The front brake light switch fails, often due to cold weather; removing the rubber cap can temporarily fix it.
Premature chain and sprocket wear

drivetrain occasional

Chain and sprockets may require replacement as early as 2500 miles due to stiff links, not covered under warranty.
Coolant leak

cooling rare

Coolant can leak from a faulty radiator cap or hose connections.
Oil leaks

engine rare

Recurrent oil leaks from unspecified engine seals or gaskets; reported on low mileage bikes.