KTM 125 Duke 2017-2020 Service Manual

The 2017 125 Duke was a major update of KTM’s A1-licence learner bike, with a powder-coated steel trellis frame, a new side-mounted silencer to pass Euro 4, a larger steel fuel tank (2.4 litres bigger) and standard ABS, which made it the first 125cc bike to have ABS as standard. The chassis has a WP 43mm upside-down fork, a WP monoshock and a four-piston radial front brake, so it handles like its bigger Duke brothers, and it’s about 10kg heavier than the first 125 Duke. It’s A1 compliant with a conventional clutch and a mechanical throttle, and it tops out at about 70 mph. Later bikes (2019-2020) were revised with updated ABS and a lower seat.

The engine is a 124.7cc liquid-cooled four-stroke DOHC single with four valves, a 58mm x 47.2mm bore and stroke and a 12.8:1 compression ratio (some later specs list 14.5:1), with fuel injection through a 33mm throttle body. KTM claims about 15 hp (11 kW) at 10,000-10,500 rpm and 12 Nm (8.9 lb-ft) of torque at 7,000-8,000 rpm. The gearbox is a six-speed with a wet multi-disc clutch (mechanically actuated) and X-ring chain final drive (14/45 sprockets).

The frame is a steel trellis design with a 65-degree steering head angle, a 43mm WP upside-down fork with about 142mm (5.6 inches) of travel and a WP monoshock with about 150mm (5.9 inches) of travel. Brakes are a 300mm front disc with a four-piston radial fixed caliper and a 230mm rear disc with a single-piston floating caliper, with Bosch ABS (two-channel on the 2017-2018 bikes, with a single-channel system listed on later bikes). The rear tire is a 150/60 ZR17 and the front a 110/70-17. Trail is about 95-100mm on a 1,357mm (53.4-inch) wheelbase, with about 155-185mm of ground clearance.

Seat height is about 830mm (32.7 inches), listed as 818mm on the later bikes. The tank holds about 13.4 litres (3.5 gallons). The 125 Duke weighs about 128-139 kg (282-306 lbs) dry and about 150 kg fully fuelled.

This factory service manual covers the procedures, torque specs, and diagrams needed to keep a 125 Duke running the way it was built to.