This single-cylinder naked model line began in 1994, when KTM introduced its first street motorcycle wearing the DUKE nameplate. The original machine arrived with a large-displacement LC4 single, exposed trellis-frame styling, and a stripped-back supermoto-inspired attitude that stood apart from conventional road bikes of the period. KTM’s own anniversary history identifies that 1994 debut as the start of the DUKE story, and later official retrospectives describe the 1999 DUKE II as a sharper, more aggressive evolution rather than a break in the lineage.
The LC4-powered DUKE family remained an important part of KTM’s road range through the 2000s, culminating in the 690 DUKE era that the company highlighted as a powerful single-cylinder street bike. KTM’s official materials from the 2010s continued to refer to the 690 DUKE as the brand’s top single-cylinder naked, and company communications for model years 2018 and 2019 still listed the 690 DUKE in the DUKE range. That makes the line significant as KTM’s long-running bridge between the company’s off-road roots and its modern naked-bike identity.
Historically, this nameplate helped define KTM’s street-bike character before the brand expanded into multi-cylinder DUKE models. It is remembered for its minimal bodywork, lightweight feel, and unapologetically raw roadster approach, which helped establish the DUKE as one of the most recognizable performance naked motorcycles of the era.