Small KTMs now have BIG ideas: Radical reinvention for all-new 125, 250 and 390 Dukes

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It’s been a decade since KTM introduced the 125 Duke and the larger 250 and 390 single-cylinder models followed soon after. Now the line-up is on the verge of a top-to-toe revamp including all-new mechanical parts and a near-production example has been spotted on test near the Austrian factory.

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The bike you see here is believed to be the mid-line 250cc model – a version that isn’t currently offered in the UK market – but if KTM follows the previous path then the 125, 250 and 390 will be almost indistinguishable with their badges removed.

The current models share the same frames and styling, and it’s clearly cost-effective to use as many common components as possible so KTM aren’t likely to take a different route in the future.

Starting with the engine, this prototype clearly runs a single-cylinder, water-cooled motor, but it doesn’t appear to share much with the existing 125, 250 or 390. The cases are new, and what we can see of the cylinder casting and head also looks to be unlike any of KTM’s current motors.

KTM 250 Duke side view

In 125cc form the next-gen Duke will inevitably stick to the legally mandated 15hp peak power to remain learner-legal, but the 250cc and 390cc engines won’t be similarly hamstrung, so KTM will be looking for increases over the current versions’ 29.5hp and 43hp respectively.

The new frame moves away from the current models’ design, which has a wide main tube with thinner pipework slung below to reinforce it. Now there are thick, parallel upper and lower tubes connected by triangulated struts, more like a traditional trellis.

Cast alloy hangers hold the front of the engine, but the really remarkable element is the vast casting that forms the entire seat subframe, replacing the steel unit that’s used at the moment.

The new cast-alloy swingarm retains the external bracing that’s been a KTM signature for years but adds an upper brace on the left-hand side. On the right, it now bananas over the exhaust exit.

KTM 250 Duke rear

Brembo’s budget ByBre brand supplies the single front and rear calipers and the suspension is WP kit. The Apex forks look chunkier than anything used on the current 390, 250 or 125 Dukes, but there’s no sign of damping adjusters.

There’s a hint of 1290 Super Duke in the styling of the bike with side panels jutting out and a self-supporting seat unit. The headlight doesn’t appear to be the finished unit. Panels either side suggest the final version will have a more familiar KTM ‘face’.

With five ultra-thin spokes, the wheels are a new design and a further indication that the bike is close to production readiness. It looks like KTM is preparing to launch at least the first versions of the new Duke as part of its 2022 model range.

Here's Neevesy's video review of the existing 125 and 390cc KTM Dukes:

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Jordan Gibbons

By Jordan Gibbons

News Editor, owns some old bikes. Should know better.