Triumph Speed T4 Spied Testing — New 350 cc Engine On Cards

A test mule of the Triumph Speed T4 was recently spied on Indian roads. While on the first glance the prototype looks visually very similar to the current Speed T4, there are chances that the motorcycle is due for a significant mechanical change. It is already well established that the Triumph is working on a new 350 cc engine and the latest unit could be a test bed for the new powertrain.

As we previously reported, Triumph is developing this new 350 cc engine to lower the taxes on its current 400 cc lineup. Under the new GST regime that came into effect on 22 September 2025, two-wheelers with an engine displacement greater than 350 cc are taxed at 40 percent whereas those with an engine smaller than 350 cc are taxed at 18 percent.

The new engine with a smaller displacement will allow the Triumph bikes to avail the benefits of a lower GST rate. The reduction in taxes is expected to contribute to a significant price reduction, making it more attractive in the eyes of prospective buyers. We expect a price drop of around  ₹20,000 to ₹ 25,000 than the existing model. The current 398 cc unit powers Triumph models such as Speed 400, Speed T4, Scrambler 400 X, Scrambler 400 XC, and Thruxton 400.

Earlier, Rajiv Bajaj, MD and CEO of Bajaj Auto, had confirmed that the new Triumph 350 cc range will be launched in April 2026. In all likelihood, Triumph will retain the basic architecture of the 400 cc engine in most parts, although the combustion characteristics could change. For instance, the compression ratio can be adjusted and the combustion chamber refined to achieve a more optimised operating state. 

Also READ: Triumph 350 Bikes Are Ready, Will They Revive India Sales?

The piston crown may also be redesigned to improve combustion efficiency. In addition, ECU remapping could introduce revised fuel injection maps and updated ignition timing, helping enhance throttle response and overall efficiency. Further refinements may extend to the camshaft, valve timing, airbox airflow, coolant flow mapping, and clutch tuning to improve the engine’s overall performance and responsiveness.

Meanwhile Bajaj, who manufactures the 400 cc Triumph motorcycles in India, hasn’t divulged any details about the new engine. Our estimate is that the loss in 50 cc of engine displacement could lead to a power drop of around 5 bhp. Besides Triumph, Bajaj is also looking to introduce 350 cc versions of Pulsar NS400Z and Dominar 400 models.

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