The 2025 Beta 300 RX transforms what was once a modified enduro platform into a purpose-built, race-ready two-stroke motocross machine. What did it take to do that? This model sets itself apart with its all-new motocross-specific chassis: a stiffer, wider frame paired with a lightweight aluminum subframe. Combined with a reworked 293cc engine that is claimed to deliver sharper power and a new five-speed transmission geared for on-track use. Keep scrolling and dive in for more.

Specifications

Changes

The 2025 Beta 300 RX features a redesigned frame with a 10mm wider main spar and reinforced sections, inspired by the 450 RX. These changes enhance both stiffness and stability. The aluminum rear subframe cuts weight while improving durability. A new design optimizes fluid temperatures and improves brake feel. The front fork now includes revised internal settings and increased travel, tailored for motocross use. Out back, the rear shock features a larger body to help reduce oil temperatures under heavy load, maintaining consistent performance during long motos. Engine updates include revised cylinder porting, a new higher-compression head, and modified crankcases, all contributing to stronger power across the RPM range. A new motocross-specific gearbox and stiffer clutch diaphragm spring improve power delivery and prevent slippage. The exhaust system features a dedicated expansion chamber and shorter silencer for optimal output. The front brake caliper is lighter and more compact, like the 450 RX's. Narrower radiators offer better cooling and a greater steering angle. X-Trig FlexFix bar mounts reduce vibration and raise bar height by 5mm, boosting rider comfort. Updated foot pegs with improved grip and reduced bulk enhance control. The smaller fuel tank lowers the center of gravity. A tool-less air filter box simplifies maintenance. The 300 RX weighs in at 219 pounds dry and carries a $9,499 MSRP.

First Impressions

The first thing that stood out was the look, this bike is visually distinct and stands apart from other motocross models with its bold red, white, and blue color scheme. Beta went their own direction instead of mimicking the competition, and it paid off. While testing at Glen Helen, I had several people comment on how sharp the bike looked. Firing it up with the electric start still gives me a kick, there’s something about a two-stroke starting at the press of a button that never gets old. It starts consistently and is easy to operate. Rolling out, the handlebars initially felt wide and straight, but the overall rider triangle felt comfortable and natural for my 5’11” frame.

On Track

Right away within my first lap or two I was really impressed with the comfort and performance of this machine as well as the overall package seems refined and I knew right away I was going to have a fun day ringing this two-strokes neck. I quickly found out this bike wasn’t only built for beauty but also built for duty as I circled Glen Helen Raceway.

Engine: The 293cc engine delivers impressive low-to-mid power and crisp throttle response. I was able to carry third gear through corners with minimal clutch work, thanks to a strong torque feel. The bike ran clean overall, though it did feel slightly rich at small throttle openings, especially during transitions from off-throttle to light input. My main gripe was with the high RPM range and over-rev. I love to stretch out a two-stroke and let it sing, but the 300 RX felt a bit flat on top and lacked the extended pull I hoped for. I found myself short-shifting to stay in the meat of the power.

It reminded me of the KTM 300 SX in that regard, though the Beta runs a Keihin PWK 38mm carb instead of fuel injection. After turning the air screw in 1.5 turns, the throttle response improved and the richness cleared up. I didn’t need any further jetting changes. Overall, the engine’s low-end torque and throttle feel were excellent, I just wanted a bit more up top.

Suspension: The KYB 48mm AOS fork and KYB 50mm rear shock are familiar components, and as a former Yamaha test rider, I tend to have high expectations from KYB. This setup didn’t disappoint. Right away, the suspension felt balanced and comfortable. The fork performed well from initial stroke through mid-travel, offering a predictable feel over bumps. Both ends felt smooth and progressive. At my 175-180 lb weight, the bike felt slightly soft, particularly under load, with some front-to-rear pitch. To improve it, I made the following changes:

• Shock: 3 clicks stiffer low-speed compression, 2 clicks slower rebound, ¼ turn in on high-speed compression
• Fork: 2 clicks stiffer compression, 2 clicks slower rebound

These adjustments gave me more hold-up and improved control through fast sections and big bumps, without sacrificing plushness. The suspension was the standout of the day for me: comfortable, capable, and well-tuned for serious riding.

Chassis: The new chromoly double-cradle frame features a wider backbone for improved rigidity and a redesigned rear brake master cylinder mount to enhance modulation and manage fluid temps. On track, the chassis felt stable and predictable, especially through smaller bumps. Beta nailed the balance of lightweight feel and planted stability. I did notice some front-to-back movement at higher speeds, like coming down Glen Helen’s hills or into Talladega, but it wasn’t unsettling. I prefer a calmer chassis, and while the Beta wasn’t quite as composed as some aluminum frames, it was close. After firming the suspension, much of that "busy" sensation went away. Credit to Beta, too, for the bold red frame, as it pops on track and on the stand.

Other Features: Ergonomically, the bike mostly felt spot on. My only complaint was with the handlebars, they felt too wide and straight for my liking, but trimming a few millimeters would likely fix that. The seat was excellent: just the right firmness and grip, and the quick-release system using two buttons is a fantastic feature. The 300 RX also includes two map settings, controlled via a cleanly integrated switch on the handlebar pad. Map one (sun) delivered a snappier low-end response, while map two (rain) softened initial power and extended the pull. Both maps worked well and were easy to toggle. The Brembo hydraulic clutch was another highlight, offering light pull and smooth engagement that mimicked a well-tuned cable setup, something I personally prefer. The bike felt slim through the bodywork, which helped overall control. However, when trying to correct a low front-end angle mid-jump, I found it hard to grip the side panels due to their narrow shape. Aside from that, the bike moved well under me and the bodywork never got in the way.

The Last Word

This bike exceeded my expectations. From its responsive engine and plush yet capable suspension to its improved chassis and thoughtful features, I came away genuinely impressed. Sure, I had a few minor complaints, mainly the top-end power and a touch of chassis activity at speed, but overall Beta has delivered a seriously fun and competitive two-stroke motocross machine. After riding this, I’m now even more excited to throw a leg over the upcoming 350 two-stroke. I’ll also be comparing the 300 RX head-to-head with the KTM 300 SX soon to find out who really builds the best 300cc two-stroke for 2025.