The Beta 350 RX 2-Stroke is built to bring big-bore two-stroke power to the motocross track — combining a massive 352cc engine, strong low-to-midrange torque, and a lightweight race-focused chassis into a machine that's unlike anything else in the class. Its all-new liquid-cooled two-stroke engine features a dual-spark-plug cylinder head, Beta Progressive Valve (BPV) power valve system, counter balancer, and Keihin PWK 38mm carburetor, delivering the strong, broad power that makes a 350cc two-stroke so unique while keeping the bike predictable and manageable. The five-speed transmission and 14/47 final gearing put that power to the ground effectively, while electric start means getting back on the gate is as simple as pushing a button. At roughly 220 lbs dry, the 350 RX combines its big-bore engine with a chromoly steel chassis, KYB 48mm closed-cartridge forks with 12 inches of travel, and a fully adjustable KYB rear shock with 11.8 inches of travel. Add 260mm front and 240mm rear brakes, full-size 21"/19" wheels, Xtrig FlexFix handlebar mounts, and no-tools air-filter access, and the 350 RX is a serious motocross machine built around one goal: delivering the torque and character of a big-bore two-stroke with the control and rideability to put it to work on the track.
Engine: Beta-built single-cylinder, 2-stroke, liquid-cooled, counter-balanced
Displacement: 351.7cc / 352cc
Bore x Stroke: 78mm x 73.6mm
Power Valve: Beta Progressive Valve (BPV), adjustable
Cylinder Head: Dual spark plug
Fuel System: Keihin PWK 38mm carburetor
Lubrication: Pre-mix
Ignition: AC-CDI Kokusan
Clutch: Wet diaphragm-style, hydraulic
Transmission: 5-speed
Final Drive: O-ring chain, 14/47 gearing
Starting: Electric start; optional backup kick starter
Weight: 220.5 lbs / 100 kg dry
Frame: Molybdenum steel double-cradle
Seat Height: 37.2"
Ground Clearance: 13.4"
Wheelbase: 58.7"
Fuel Capacity: 1.5 gallons
Front Suspension: 48mm KYB AOS closed-cartridge fork, compression and rebound adjustable
Rear Suspension: KYB 50mm shock, rebound and high/low-speed compression adjustable
Front Wheel Travel: 12.0"
Rear Wheel Travel: 11.8"
Front Brake: 260mm floating rotor
Rear Brake: 240mm rotor
Wheels: 21" front / 19" rear
Tires: 80/100-21 front / 120/80-19 rear
Key Features: Dual-spark cylinder head, BPV power valve, counter-balanced engine, electric start, KYB suspension, Xtrig FlexFix bar mounts, quick-access air filter
Pure Motocross. No Compromises.
The Beta 250 RX is built for riders who want a purpose-built 250cc two-stroke motocross machine with explosive power, precise handling, and race-ready performance. Its 249cc liquid-cooled 2-stroke engine delivers the quick throttle response and hard-hitting power that make a 250 two-stroke so exciting to ride.
Designed specifically for the motocross track, the 250 RX features a competition-focused chassis and suspension setup designed to handle jumps, whoops, berms, and aggressive cornering. The result is a bike that feels light and responsive while giving experienced riders the confidence to push harder.
The 249cc engine, Beta Progressive Valve power system, 5-speed transmission, electric start, and race-focused suspension make the 250 RX a serious contender straight out of the crate. Whether you're lining up at the gate or putting in laps at your local track, the 250 RX is ready to race.
Why the 250 RX?
249cc liquid-cooled 2-stroke engine
Beta Progressive Valve (BPV) power valve
Electric start
5-speed transmission
Wet multi-disc clutch
Competition-focused motocross chassis
Race-tuned suspension
Powerful hydraulic disc brakes
21" front / 19" rear wheels
Lightweight two-stroke design
Built specifically for motocross
PURE MOTOCROSS PERFORMANCE. BUILT TO WIN.
The 2026 Beta 450 RX is Beta’s high-performance 450cc motocross machine, combining serious race-winning power with the precise handling and rider-focused ergonomics Beta is known for. For 2026, Beta made major engine updates to deliver stronger torque and a broader, more usable powerband while keeping the bike controllable and predictable on the track.
At the heart of the RX is a 449.3cc liquid-cooled, single-cylinder four-stroke engine with a 5-speed transmission, electric start, dual engine mapping, and traction control. The 2026 model features a newly developed cylinder head, revised intake manifold, performance-enhanced piston, redesigned exhaust system, and updated engine mapping for improved overall performance.
Key Features
449.3cc 4-stroke, 4-valve engine
5-speed transmission
Electric start
46mm throttle body
Dual-map ignition with traction control
Adjustable hydraulic diaphragm multi-plate clutch
48mm KYB AOS closed-cartridge front fork
KYB rear shock with progressive linkage
260mm floating front brake rotor
240mm rear brake rotor
21" front / 19" rear wheels
DID rims
80/100-21 front tire
110/90-19 rear tire
1.5-gallon fuel capacity
37.2" seat height
13.2" ground clearance
58.1" wheelbase
230.4 lb dry weight