Yamaha DT125 A B C 1974-1976 Service Repair Workshop Manual

Wikipedia's own model history frames the DT125's genuine staying power directly: "the Yamaha DT125 is a motorcycle produced by Yamaha Motor Company that was first launched in 1974 as the DT125A and is still sold in some markets to this day" — a genuinely remarkable production span for a single nameplate, with this 1974-1976 A/B/C generation representing the model's earliest, most mechanically straightforward form before Yamaha's later Mono-cross suspension update arrived in 1977.

Power comes from a 123cc air-cooled two-stroke single with reed-valve induction, delivering a claimed 17.33 hp at 7,000 rpm and a genuine 81 mph top speed on later, more developed versions of this engine architecture — though Wikipedia's own spec sheet notes this earliest 1974 A-model ran a 5-speed transmission rather than the 6-speed gearbox that arrived on subsequent DT125 generations. The DT designation itself signals the model's fundamental purpose: a two-stroke, off-road-styled motorcycle with a raised exhaust, cross-braced handlebars, universal (dual-purpose) tires, and genuine ground clearance for real trail work, not just cosmetic dirt-bike styling bolted onto a street commuter.

Chassis hardware across this original generation includes a cradle-style tubular steel frame, conventional telescopic front forks, and a dual-shock swingarm rear end — Wikipedia's own account specifically notes "1974 is not a monocross," distinguishing this early A/B/C generation from the single-shock Mono-cross rear suspension Yamaha introduced across its DT lineup starting in 1977. Front and rear braking used drums at both ends on this earliest generation, before disc brake options arrived on later DT125 iterations. Fuel capacity sits at 9.5 litres (2.5 US gallons), with a claimed dry weight around 256 lbs — genuinely light and manageable for riders learning to handle a proper off-road-capable machine on varied terrain. Because this range shares its fundamental engine architecture, frame design, and service procedures with the smaller DT100 and larger DT175 sold alongside it during the same 1974-1976 span, Yamaha's own factory documentation covers all three displacement classes together in a single combined workshop and parts manual.

This factory service manual covers the engine overhaul, carburetion service, and complete maintenance procedures needed to keep a 1974-1976 DT125 A/B/C running the way Yamaha built it.