Why India's new 400cc bikes have 349cc engines: the 350cc GST line explained

If you walked into a Triumph or KTM showroom this year and found that the Speed 400 and the Dominar 400 now have engines smaller than 350cc, there is one reason: tax. India taxes a petrol two-wheeler at 18 per cent GST up to 350cc. Cross that line by even one cubic centimetre and the rate is 40 per cent. So makers have reworked their 400cc singles to land at 349cc, kept the old nameplates, and passed on the difference.

The line, and what crossing it costs

Autocar Professional reported in September 2025 that the GST Council pushed motorcycles above 350cc to 40 per cent, up from 28 per cent plus a 3 per cent cess, with the new rates effective from 22 September 2025. The same report notes that bikes above 350cc are just 1 per cent of India's two-wheeler market, which is exactly the premium 250 to 650cc space this desk covers.

That one slab decides a lot. A Royal Enfield 650 twin, a Himalayan 450, a Harley-Davidson X440 and a 399cc KTM all sit on the wrong side of it. A Classic 350, a Hunter 350 and a Honda CB350 were already on the right side. Eicher's Siddhartha Lal had publicly argued for a uniform 18 per cent rate across all two-wheelers, Autocar Professional reported, but the split stayed.

How the engineers got under 350cc

Triumph did it with the stroke. Autocar India reported on 6 April 2026 that the India-built 398.15cc single becomes a 349cc unit, with the bore unchanged at 89mm and the stroke cut from 64mm to 56.1mm. Triumph kept the 400 nameplates. Prices fell by ₹7,000 to ₹11,000 depending on the model, with the Speed 400 at ₹2.32 lakh and the Thruxton 400 at ₹2.66 lakh, ex-showroom Delhi. Outputs now range from 29hp on the Speed T4 to 40hp on the Tracker 400 and Thruxton 400.

Bajaj did the same across three brands. Its 22 April 2026 release launched the new Dominar 400 with a 350cc engine at ₹2,03,214 ex-showroom Delhi, which it called almost ₹37,000 lower than before, making 40.6 PS at 9,000rpm and 33.2 Nm at 7,500rpm. On 30 April 2026 the Pulsar NS400Z moved to a 349cc engine at ₹1,80,092, with Bajaj claiming savings of up to ₹24,500 once the lower insurance and registration costs that follow the smaller engine are counted.

KTM took a different route. On 20 April 2026 Bajaj announced 350cc variants of the 390 Duke and 390 Adventure at ₹2,77,268 and ₹2,80,905 respectively, making 41.5 PS and 33.5 Nm, while the 399cc models continue on sale.

What you actually give up, and what to check

Power, mostly. Bajaj's own February 2025 release puts the 399cc LC4c at 46 PS and 39 Nm, so the 350cc KTM gives up 4.5 PS and 5.5 Nm. On the Bajaj twins the drop is smaller because those engines were never near 46 PS.

Three practical points for a buyer. First, the badge and the paperwork will not match, so read the displacement on the RC and the insurance policy, not the tank. Second, third-party insurance and state road tax are slabbed by engine capacity, which is why Bajaj talks about on-road savings rather than ex-showroom alone. Third, if you want the bigger engine, buy it now while it is still listed, because KTM sells both and Triumph does not.

Nothing changes for a bike already in your garage. A 2024 Speed 400 stays a 398cc bike with its original output, and resale will treat the two engines as different machines.

Sources

• GST on 350cc-Plus Motorcycles Hiked to 40% from 28%, Autocar Professional
• New Triumph 350cc models price and specifications revealed, Autocar India
• Bajaj Auto launches the new Dominar 400, now with a 350cc engine, unlocks ₹37,000 price benefit
• All New Pulsar NS400Z unlocks savings up to ₹24,500 with 18% GST benefit, Bajaj Auto
• KTM expands its KTM 390 Duke and KTM 390 Adventure range with 350cc engine, Bajaj Auto
• KTM 390 Duke: the corner rocket is now at Rs 2.95 lakh, Bajaj Auto