Triumph Bonneville 400 Spied Testing Again Ahead Of Launch

The Triumph Bonneville 400 has been spotted testing in India once again, signalling that the motorcycle's launch is drawing closer. The Triumph Bonneville 400 is expected to debut in India around September 2026.

Spy shots of the Triumph Bonneville 400 mule spotted from this latest round of testing by Instagram user @mane_the_omkar reveal styling and hardware changes that set the Bonneville 400 apart from the Speed 400 it is based on. The Bonneville 400 is shaping up to be a proper retro-styled sibling rather than a mild visual rework of the existing roadster.

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Triumph Bonneville 400: Design And Styling

The test mule of the Triumph Bonneville 400 shows a different chassis and a new swingarm compared to the Speed 400. Triumph also appears to have redesigned the rear subframe to support a flatter, bench-style seat that gives the bike a more authentic Bonneville profile.

The Bonneville 400 looks noticeably larger and bulkier than the Speed 400 in these images. It gets a bigger fuel tank, long and rounded side panels, and chunkier front and rear fenders, bringing its proportions closer to the Royal Enfield Classic 350.

Retro touches spotted on the test mule of the Triumph Bonneville 400include a peashooter exhaust, chrome-finished engine crankcase covers, chrome rear grab rails, and chrome detailing on the exhaust.

Triumph Bonneville 400: Engine And Hardware

Power for the Triumph Bonneville 400 will come from the same 349cc, liquid-cooled, single-cylinder engine, which is shared with the Speed 400. The tuning is expected to favour a relaxed, modern-classic character suited to the Bonneville's laid-back positioning.

Triumph has retained familiar running gear on the Bonneville 400 borrowing from other bikes in its 400 lineup. The bike gets conventional telescopic front forks, twin rear shock absorbers, and wire-spoke wheels.

Triumph Bonneville 400: Launch Timeline

The Bonneville 400 is expected to reach Indian showrooms around September 2026. Triumph has not yet revealed full specifications or confirmed pricing for the upcoming Triumph Bonneville 400, which will rival the likes of the Royal Enfield Classic 350 and the Honda CB350 H'Ness.