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The KTM 390 Duke is the fastest of the three bikes in one published comparison: it lists a maximum speed of 160 km/h, ahead of the Yamaha MT-03 at 155 km/h and BMW G 310 R at 143 km/h. These are comparison-page figures, not results from a documented, controlled head-to-head test. They do not establish the fastest naked bike under 400cc overall.
How the listed top speeds compare
MotorradTest.de lists the following maximum speeds for three naked bikes. The comparison page does not state a common test method or year for these figures, so treat them as published estimates rather than verified, like-for-like measurements.
| Motorcycle | Listed maximum speed | Source qualification |
|---|---|---|
| KTM 390 Duke | 160 km/h | MotorradTest.de comparison page; year and measurement method not stated. |
| Yamaha MT-03 | 155 km/h | MotorradTest.de comparison page; year and measurement method not stated. |
| BMW G 310 R | 143 km/h | MotorradTest.de comparison page; year and measurement method not stated. |
Within this three-bike comparison, the KTM has the highest listed figure. The 5 km/h gap between the KTM and Yamaha, and the 12 km/h gap between the Yamaha and BMW, should not be read as proven differences under identical conditions.
See the MotorradTest.de comparison.
Why this is not a complete under-400cc ranking
The Kawasaki Z400 is an important candidate that the three-bike speed comparison does not cover. Kawasaki Motors Japan’s 2026 specification page lists its displacement as 398 cm³ and power as 48 PS, but a comparable Z400 top-speed figure is not established by the sources here. It would be misleading to rank it above or below the other bikes based on engine output alone.
#1 Best Overall
- Wide Compatibility: Fits most motorcycles from 125cc to 400cc with standard indicator mounts—ideal for both street and off-road bikes.
- Bright Amber LED Light: High-intensity glow improves visibility and enhances safety during both day and night rides.
- Durable & Long-Lasting: Made from tough, unbreakable plastic to resist shocks, vibrations, and extreme weather conditions.
- Universal Fit Design: Suitable for front or rear installation on a wide range of motorcycles and bike models.
- Hassle-Free Installation: Plug-and-play system with no tools or rewiring required.
Availability and specifications vary by region and model year. The available manufacturer pages represent different markets, not one universal lineup: KTM Australia for 2025, Yamaha Europe for 2025, and Kawasaki Japan for 2026. Kawasaki Europe also has a page for the 2023 Z400, which is not interchangeable with a current Japanese model specification.
Kawasaki Motors Japan: 2026 Z400 specifications · Kawasaki Europe: 2023 Z400.
Rank #2
- Flowing Amber LED Turn Signals – Features dynamic sequential lighting that enhances visibility and gives your motorcycle a sleek, modern upgrade.
- Universal Compatibility – Designed to fit most bikes including sportbikes, cruisers, scooters, and street motorcycles. Ideal for 125cc–400cc models.
- Ultra-Bright LEDs for Maximum Safety – High-intensity amber LEDs ensure you're seen clearly during day or night, increasing safety while turning or braking.
- Weatherproof & Durable Design – Made from premium-grade materials to resist rain, dust, and vibrations. Perfect for tough road and off-road conditions.
- Quick Plug-and-Play Installation – Simple 2-wire setup. No modifications required. (Note: Package includes only LED indicators; connectors not included.)
Engine specifications, with market and year attached
Manufacturer specifications help explain what each bike offers, but displacement, power and torque do not directly verify maximum speed. These figures apply to the specific regional pages cited:
| Motorcycle and specification page | Displacement | Peak power | Peak torque |
|---|---|---|---|
| KTM 390 Duke, Australia-market 2025 | 398.7 cm³ | 45 PS | 39 Nm |
| Yamaha MT-03, Europe-market 2025 | 321cc | 42.0 PS | 29.5 Nm |
| Kawasaki Z400, Japan-market 2026 | 398 cm³ | 48 PS | 37 Nm |
| BMW G 310 R, historical launch release | 313 cc | 34 hp (25 kW) at 9,500 rpm | 28 Nm at 7,500 rpm |
The BMW figures come from its launch announcement and are historical, not confirmation that specifications are unchanged in every current market. BMW described the G 310 R at launch as “the first BMW roadster under 500 cc.”
Rank #3
- Part Numb: Replaces and matches part numbs 21003-1214 and 21003-1368 specification engine stator components.
- Fitment: Compatible with 400, -II, ZZR400/500/600, and -6R/-6 sies naked street, sport touring, and sportbike inline-four engine motorcycles.
- Specifications: 12V opating voltage standard, with and copp windings precisely calibrated to meet 400cc to 600cc displacement high-RPM inline-four engines electrical and ignition demands.
- Structure: Features high-pmeability lamination cores, heavy-duty insulated high-tempature resistant copp wire ( to 200°C), integrated pick-up pulsar coil, and a dedicated connector wiring harness.
- Installation: Stator plate mounting configurations, cent diamet, and wiring coupls align precisely with the engine crankcase base for a direct replacement.
KTM Australia: 2025 390 Duke specifications · Yamaha Europe: MT-03 specifications · BMW Group: G 310 R launch release.
What determines the speed a rider can actually reach
A listed maximum speed is not a promise of attainable speed on the road. The comparison page does not identify the test conditions behind its figures. Actual results can vary with model year and configuration, rider and equipment, wind, road grade, vehicle condition, instrumentation and test method. A speedometer reading, manufacturer claim and independently measured GPS result are not automatically equivalent.
Rank #4
- Stable signal triggers when the clutch lever is squeezed, enabling safe start and preventing accidental takeoff in gear.
- Made of durable engineering plastic housing, anti-shock and anti-aging for outdoor riding conditions.
- Sensitive contact with quick response, ensuring stable operation of the clutch circuit.
- Temperature resistant, maintaining stable performance in various weather conditions.
- Safety protection switch that effectively improves riding safety and prevents unexpected vehicle movement.
For a meaningful comparison, look for figures gathered under the same conditions and check whether the source explains how speed was measured. The sources cited here do not provide a controlled common test for the KTM, Yamaha, BMW and Kawasaki.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to use these figures when choosing a bike
- If you are comparing only the three listed bikes: the KTM 390 Duke leads the cited comparison at 160 km/h, followed by the MT-03 at 155 km/h and G 310 R at 143 km/h.
- If the Z400 is on your shortlist: confirm the specification and availability for your country and model year; the cited 2026 Japanese page gives engine data, not a comparable top-speed result.
- If top speed is decisive: seek a source that names the model year, market, measurement method and conditions rather than relying on a bare maximum-speed number.
- If you are choosing for everyday riding: compare local availability and the specific model’s ergonomics, equipment, handling and weight using evidence for the exact version you can buy. The figures above do not settle those questions.
BMW Motorrad Malaysia lists optional G 310 R accessories including a luggage rack, topcases, heated grips and a 12 V power outlet/USB charging socket. Those options are specific to its Malaysia-market page; confirm local availability and model fitment with a dealer.
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- Configuration: features a twin-cylinder engine cylinder block and 68mm piston component set
- Adaptation: matches specific 2018-2023 400cc sport and naked motorcycles utilizing the Ninja400, EX400, and Z400 engine architecture
- Construction: manufactured with sturdy components to withstand daily operational wear
- : supplies compression sealing to help manage combustion force transfer during operation
- Integration: aligns closely with vehicle crankcase mating surfaces for a straightforward mount
BMW Motorrad Malaysia: G 310 R data and optional equipment.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
