Beta has revamped its lineup of two-stroke motocross bikes for 2026. Gone is the 300 RX, replaced by the 250 RX and 350 RX. This provides riders in the 250 two-stroke classes a bike to race, while making the big-bore two-stroke even easier to ride. Both bikes have significant updates compared to the 300 RX they are supplanting, and are virtually identical, except for displacement and engine tuning. Let’s see what the 2026 Beta 2-stroke MX lineup is all about.
- The engines get major upgrades for 2026. The crankcase is new, with each engine getting its own crankshaft. The cylinders and pistons are all new, reflecting a change in displacement from the 300. Additionally, the radiators are more durable than those from last year.
- The 250 RX is a long-stroke motor, while the 350 RX is a short-stroke mill. Despite that, the 250 delivers “explosive performance” according to our Beta source, while the 350 has “linear power delivery”. The 350’s bore is 11.6mm larger than the 250, and its stroke 1.6mm longer.
- The motors have distinctive cylinder heads. The 350 has a two-plug head, while the 250 gets a traditional single spark plug.
- The power valve on each bike uses a different spring to cater to each powerband. The power valve is still adjustable and progressive. Also, the expansion chambers and mufflers are optimized for each engine.
- There are two power modes—Wet and Dry. If you want traction control, you’ll have to get the four-stroke 450 RX.
- Each 2-stroke RX gets the same transmission. However, the 350 is geared higher thanks to a three-tooth smaller rear sprocket.
- The frame is unchanged, and the KYB suspension returns. According to Beta insiders, the suspension is dialed in for “rideability and stability.” The rear subframe has an MX-specific airbox that enables tool-free air filter swaps. Dunlop Geomax MX34 tires are mounted on blue-anodized Takasago Excel 21-/19-inch rims.
- We don’t have a price for the 2026 Beta 2-stroke MX lineup yet. Beta has plenty of time to settle on the price, as the two motocrossers won’t arrive in the United States until September. While you don’t have any choices of color, the graphics are all-new for ’26.
2026 Beta 250 RX (and 350 RX) Specs
ENGINE
- Type: Single-cylinder 2-stroke w/ counterbalancer
- Displacement: 249cc (350: 352cc)
- Bore x stroke: 66.4 x 72mm (350: 78 x 73.6mm)
- Compression ratio: 14.6:1 (12.45:1)
- Induction: Case reed
- Fueling: Keihin PWK 38mm
- Exhaust: Adjustable progressive power valve
- Starting: Electric (optional backup kickstarter)
- Lubrication: Premix
- Transmission: 5-speed
- Clutch: Wet diaphragm-style
- Final drive: Chain
CHASSIS
- Frame: Double-cradle chromoly steel
- Front suspension; travel: Compression- and rebound-damping adjustable 48mm inverted KYB AOS Closed Cartridge fork; 12.0 inches
- Rear suspension; travel: Linkage-assisted, fully adjustable KYB piggyback-reservoir shock; 11.8 inches
- Rims: Excel Takasago
- Tires: Michelin StarCross 5 Medium
- Front tire: 80/100-21
- Rear tire: 120/80-19
- Front brake: 260mm Galfer rotor w/ 4-piston Nissin caliper
- Rear brake: 240mm Galfer rotor w/ 2-piston Nissin caliper
DIMENSIONS and CAPACITIES
- Wheelbase: 58.7 inches
- Seat height: 37.2 inches
- Ground clearance: 13.4 inches
- Fuel tank capacity: 1.5 gallons
- Wet weight: 230 pounds
2026 Beta 250 RR Price: $TBA MSRP
2026 Beta 350 RR Price: $TBA
2026 Beta 2-Stroke Motocross Lineup Photo Gallery
