Ryan Nitzen | May 14, 2023
The Beta 300 RX and KTM 300 SX go head-to-head, toe-to-toe in our “open-class” two-stroke motocross duel.
Photography by Kit Palmer
The pro supercross and motocross ranks might have snuffed out two-stroke competition almost entirely, but the diehards never loosened their grip on the premix. Two-stroke development maintained a pulse throughout the four-stroke revolution, largely in thanks to Yamaha and KTM, and ironically, it’s only now, nearly two decades after factory teams shifted their focus to four-strokes, that we’re seeing the emergence of a new open-class contender in the camless ranks. The 300cc two-stroke—an already iconic weapon in the world of off-road competition—has made its way into the motocross scene with MX-specific offerings from major manufacturers, KTM and Beta. Italian manufacturer TM also offers the MX300 ES 2T, and there are also some slick big-bore kits out there for your 250, but in this open-class two-stroke showdown, we’re squaring off with these two major players: the 2023 KTM 300 SX and Beta 300 RX.
The open-class two-strokes are making a comeback. It’s about time.
In This Corner
In the red corner, you have the Beta 300 RX. The Italian brand continues to make waves as it grows in popularity, especially in the U.S. The 300 RX is the company’s lone motocross bike among a plethora of enduro, dual-sport and trials machinery. It uses KYB suspension components, including a 48mm closed-cartridge coil-spring fork. The Beta weighs in at 234 pounds with its 2.5-gallon tank topped off.
The Beta is fueled via a 38mm Keihin carburetor and has a manually adjustable exhaust power valve, an electric starter, and a six-speed transmission. It also has two ignition maps to choose via an in-cockpit switch.
In the orange corner, you have the KTM 300 SX. This bike is also a new model for KTM that was introduced about this time last year. It’s fitted with WP suspension, including a WP Xact AER (air) fork. All KTM SX full-size (motocross) two-stroke models utilize its new throttle body (TBI) fuel-injection technology. This replaced the transfer port injection (TPI) on the off-road models, and the traditional carburetor on the SX models. With the SX, you also have two pre-programmed maps that you can choose via a button on the handlebar, and when you change maps, you’re also changing the operation of its new electronic exhaust power valve. In the standard setting, the power valve opens all the way when you see a green light blinking, so you’re getting the most out of the engine. In the other position, the power output is altered when you see a white light blinking, with the power valve only opening at 80 percent to help make the power output a little more manageable for the rider. You cannot adjust the power valve separately. It’s a one-package deal that works harmoniously with the bike’s CPU, which operates fuel mapping and spark advance.
The KTM has a five-speed gearbox and weighs 232 pounds with a full gas tank.
There is plenty to like about both bikes.
Match Up
On paper, the KTM and Beta have several similarities. They weigh within a couple pounds of each other, have the same 293cc displacement and square 72 x 72mm bore and stroke configuration, use hydraulically operated clutches, and use the same disc brake manufacturer, Brembo. Their wheelbases are nearly identical, and they both rely on steel frames. They both have electric starters, which is the norm nowadays. (Beta, however, offers a kickstart back-up option, the KTM does not). The KTM holds approximately a half-gallon less fuel.
Technically, the main differences between these two motorcycles are their fueling systems (FI versus carb), transmissions (six-speed versus five-speed), and forks (air versus coil spring).
And there is also price $9199 (KTM) versus $9399 (Beta).
The Beta 300 RX is darn good right from the get-go for a brand new to the motocross scene, but you can still feel its off-road heritage.
Ding!
From the cockpit, the KTM feels longer and lower than the Beta, despite what the spec sheets say. The KTM has supposedly a half-inch on the Beta when it comes to seat height, but it just doesn’t feel that way. The KTM feels roomier. The Beta’s front end (tank and shrouds) is noticeably wider than the KTM’s, but the Beta’s seat and rear end feel narrower. The Beta’s seat cushion is also stiffer. Otherwise, they feel natural between your legs and easy to adapt to, even if you’re new to either brand.
But let’s get to the meat and potatoes, specifically the meat.
Both bikes rip when it comes to their engines; there is no power shortage in either camp. Grabbing a handful of throttle on either bike is a satisfying experience. But there are subtle differences in how their power is delivered, giving them distinct personalities.
The KTM’s engine hits hard and fast. Power comes on immediately and there is zero lag or hesitation. It’s strong off the bottom but loves to sit in the mid-to-top-end range. Second and third gears are dying to be twisted to the stop. And most of the time, you don’t need to feather the clutch to bring this bike back to life should the revs drop. The low-end is so good that you can cruise it like your favorite four-stroke.
The KTM is a powerhouse and has the suspension to keep up.
We had only a few complaints with the KTM’s powerplant. There is slight pinging at high RPM, and while the meat of the power is indeed tasty, the over-rev character turns bland at the very top, but most 300s do. In short, you’re better off riding a gear higher to keep the pinging to a minimum and to stay in the powerband’s sweet spot.
The Beta’s engine stands out, too. With its classic carburetor design, this bike flat-out rips and, perhaps best of all, sounds like it’s ripping. The Beta is music to our ears.
The Beta’s initial roll-on is snappy and responsive, and you can’t help but find yourself in the juicy part of the power right away, and it is easier to stay there than it is to stay in KTM’s sweet spot. The Beta is impressive from idle to mid but not as smooth as the KTM, but we’re okay with that. Bottom-line, we’re still big fans of jets and float bowls. Yes, the KTM feels ultra-smooth and clean, which is nice, but there is something about that snappy and grungy feel we like that only carbs can provide.
With its six-speed transmission versus the KTM’s five-speed, you tend to shift the Beta less often while stretching out all the gears a bit longer. To keep the KTM in the most desirable portion of the powerband, you need to shift it more, but there is enough power everywhere to get by if you’re feeling a little lazy on the shifter. With the Beta, you only tap into sixth gear on MX tracks if it’s a wide-open and unusually fast and smooth track. It’s best to think of it as an overdrive gear, which can be helpful in high-speed cross-country-style races.
You’ll feel a difference from map to map on both bikes, more so on the KTM than the Beta. In the “mellow” maps (okay, neither are hardly mellow on either bike), the KTM and Beta feel similar, making both these very powerful motorcycles a little easier to manipulate. We never felt the need to manually adjust the Beta’s exhaust power valve (a tool is needed), but from our experiences in the past with other Beta two-stroke models, it is a handy adjustment option for fine-tuning or smoothing out the red bikes’ power delivery.
Both bikes feel light and agile compared to their 450cc four-stroke rivals.
Vibration has always been a nemesis with high-revving 300cc two-strokes. Both bikes use counter-balancers to help with this and do a great job, but the KTM is significantly less vibey than the Beta.
What sets these two bikes apart the most is their suspensions. The KTM’s suspension feels more at home for motocross, which doesn’t surprise us. KTM has more motocross experience than Beta. The Beta suspension is considerably soft for hardcore MX use, especially on big, fast, and pounding tracks like Glen Helen Raceway, where we spent much of our time testing these two motorcycles. The KTM is more MX-ready right out of the crate with top-line MX-developed WP Xact components. It’s a true SX model with a similar feel and activity as the other SX and SX-F lines in orange. It is very good stuff in stock trim.
The Beta is closer to an Austrian “XC,” closed-course stock-bike setting but even softer still. We increased clickers a lot (we lost count), but it’s just too softly sprung, and the valving needs to be customized for serious MX racers. But it’s well suited for a chill day at the track or a vet rider who isn’t so much worried about lap times and more concerned with having a good time.
The KTM feels long and stable in the handling department, with a chassis built for speed and predictability. It also turns well but more on the rear wheel than the Beta. The Beta brings front-end precision into the mix with more tree-hugging enduro-style turning (i.e., on the front tire). The Beta sacrifices a bit of straight-line stability for the ultra-precise turning. KTM wins in both suspension and chassis handling for big-track MX use.
The Beta sells for a couple hundred dollars more than the KTM but might appeal more to traditionalists with its carbureted engine and coil-spring fork.
TKO
Living in a world where big-bore two-stroke motocross beasts roam dealership floors and are let loose on motocross tracks at will is a good time to be alive. You’re going to really love riding these bikes, guaranteed. And they both provide a fun alternative to the valve-and-cam crowd for recreational track day riding and racing (if allowed in your local series).
KTM is leading the charge in motocross technology and brings its collective power of a couple decades of SX and SX-F development to the TBI-equipped 300 SX. You’re just not going to beat that very easily. It’s not as exciting as the carbureted Beta, but it works the same every time, and for the casual rider who wants to have fun, the KTM will simply do that better. It has the suspension and handling chops to suit any track and most riders. So, it’s the total package.
If you’re looking for something different, go with the Beta and enjoy a fantastic motor character, older-school vibrations through the frame, and a suspension/handling package that will need some tuning to get dialed in for the faster sections of the track. But, like the carburetor that fuels the punchy motor, tuning dirt bikes for your personal preference isn’t a terrible way to spend your day.
So, the choice is yours. Go easy with the KTM and simply ride with a smile or start with the Beta and make it your own. CN
VIDEO | 300cc 2-Stroke Showdown | Beta 300 RX vs KTM 300 SX
Beta 300 RX vs KTM 300 SX
Specifications
|
2023 KTM 300 SX
|
2023 Beta 300 RX |
| MSRP: |
$9199 |
$9399 |
| Engine Type: |
2-stroke, single |
2-stroke, single |
| Displacement: |
293.2cc |
293.1cc |
| Bore x Stroke: |
72 x 72mm |
72 x 72mm |
| Cooling System: |
Liquid |
Liquid |
| Starting System: |
Electric |
Electric (optional Kickstarter) |
| Fueling: |
Fuel Injection (Throttle Body Injection) |
Carburetor, Keihin PWK 38mm |
| Transmission: |
5-speed, w/ hydraulic clutch |
6-speed, w/ hydraulic clutch |
| Frame: |
Steel, central tube |
Steel, double-cradle |
| Subframe: |
Polyamide, aluminum |
Aluminum |
| Front Suspension: |
48mm, WP AER Xact 48mm |
48mm, KYB AOS closed-cartridge |
| Rear Suspension: |
WP Xact w/ linkage |
KYB w/ linkage |
| Front-Wheel Travel: |
12.2 in. |
12.2 in. |
| Rear-Wheel Travel: |
11.8 in. |
12.4 in. |
| Front Wheel: |
21 in. |
21 in. |
| Rear Wheel: |
19 in. |
19 in. |
| Front Tire: |
Dunlop Geomax MX-33F |
Michelin Starcross |
| Rear Tire: |
Dunlop Geomax MX-33 |
Michelin Starcross |
| Front Brake: |
Brembo 260mm |
Brembo 260mm |
| Rear Brake: |
Single 220mm, Brembo caliper |
Single 220mm, Brembo caliper |
| Wheelbase: |
58.7 in. |
58.6 in. |
| Seat Height: |
37.7 in. |
37 in. |
| Ground Clearance: |
13.9 in. |
13.3 in. |
| Fuel Capacity: |
1.90 gal. |
2.51 gal. |
| Weight (full fuel, actual): |
232 lbs. |
234 lbs. |
