Price to be announced. Contact Moto Dynamics for pricing, availability and help purchasing your bike.
Choose the engine character you want on the track
The MY27 Beta RX range offers four distinct motocross options: the 250 and 350 two-strokes, the new 250 four-stroke and the 450 four-stroke. Each combines electric start with KYB suspension, but the way it makes power—and the riding effort it asks of you—is different.
Find your RX
- 250 2T: for riders who enjoy a responsive two-stroke and working the gears. MY27 brings a longer 14/51 final-drive ratio, reinforced silencer and revised suspension settings.
- 350 2T: big two-stroke pull for riders who enjoy using torque and longer gears. Its 351.7 cc engine receives a lighter piston and PVD-treated rings for MY27, alongside model-specific KYB settings. It is a motocross bike; off-road/enduro-style riding may call for setup changes. The RX350 is not road registrable.
- 250 4T: the new smaller-capacity four-stroke, with a dedicated 249.8 cc engine, dual-injector fuel system and chassis development. Five-level launch control and an upshift quickshifter support its competition focus.
- 450 4T: for experienced riders seeking strong four-stroke drive. MY27 adds launch control and an upshift quickshifter alongside traction control and two engine maps.
Built around track use
KYB 48 mm closed-cartridge forks and a KYB rear shock provide a fully adjustable suspension platform. The RX uses a 21-inch front and 19-inch rear wheel, 260/240 mm brake discs and a 7 L fuel tank. New grips, revised handlebar positioning and a reinforced chain guide are practical MY27 updates. Suspension setup should suit your weight, pace and track conditions.
Key specifications
Specifications below are manufacturer-published reference figures. Dry weight excludes operating fluids as defined by the manufacturer; it is not a ready-to-ride weight.
| Specification | 250 2T | 350 2T | 250 4T | 450 4T |
|---|---|---|---|---|
| Displacement | 249.3 cc | 351.7 cc | 249.8 cc | 449.3 cc |
| Bore × stroke | 66.4 × 72 mm | 78 × 73.6 mm | 78 × 52.3 mm | 97 × 60.8 mm |
| Engine | Liquid-cooled two-stroke | Liquid-cooled two-stroke | Liquid-cooled DOHC four-stroke | Liquid-cooled DOHC four-stroke |
| Fuel system | Keihin PWK 38; premix | Keihin PWK 38; premix | Dual-injector EFI; 46 mm throttle body | EFI; 46 mm throttle body |
| Dry weight | 100 kg | 100 kg | 101 kg | 104.5 kg |
| Seat height | 945 mm | 945 mm | 945 mm | 945 mm |
| Transmission | 5-speed | 5-speed | 5-speed | 5-speed |
| Start | Electric | Electric | Electric | Electric |
| Wheel travel, front/rear | 305 / 300 mm | 305 / 300 mm | 305 / 300 mm | 305 / 300 mm |
These are competition motocross models. Do not assume road registration or unrestricted trail access; discuss the riding you intend to do before choosing.
Talk through your options with Md
Tell us where you ride, your experience and what you want from your next bike. We’ll help you compare the models and check current Australian specification, pricing and availability.
Pricing and availability: please enquire for a confirmed Moto Dynamics quote and supply timing. Manufacturer announcements do not confirm bikes in store. International manufacturer photographs may show competition equipment; supplied Australian equipment must be confirmed.
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