02/02/2007
The Dawn of a New Era for KTM's 2-Stroke Motocross Bikes
KTM has truly embraced innovation with their latest generation of two-stroke motocross bikes, ushering in a new era of performance and rider experience. The 2023 KTM SX range, comprising the popular 125 SX and 250 SX, now welcomes the potent new 300 SX to the MX Open category. This significant overhaul encompasses a completely redesigned chassis, fresh bodywork, and heavily revised engines. At the heart of these advancements lies the introduction of electronic fuel injection (EFI), electric start, and a host of other features aimed at elevating usability and performance, bringing the beloved 2-stroke technology firmly into the modern motocross landscape.
Electronic Fuel Injection: The Game Changer
For the first time ever, the entire full-sized KTM SX range is equipped with electronic fuel injection. This is a monumental leap forward, replacing traditional carburettors with a sophisticated system designed to provide optimal power delivery in all conditions. Working in tandem with Keihin, KTM has developed a robust 39mm throttle body specifically engineered to withstand the rigours of competitive motocross. This system is managed by a finely tuned ECU from Vitesco Technologies, which continuously monitors a multitude of parameters – including water temperature, air temperature, ambient pressure, crankcase pressure, RPM, and throttle position – to ensure the perfect air-fuel mixture at all times. The newly designed injectors further enhance this by promoting an optimal burn rate, delivering a finer fuel spray for cleaner ignition and minimised fuel wastage. This means riders can finally enjoy the benefits of a 2-stroke without the hassle of fiddling with jetting to adapt to changing conditions, offering a genuine and accessible alternative to 4-stroke machinery.
Key Technological Advancements
Reed Valve System Upgrade
The reed valve case has also seen a significant design update. New plastic flaps have been integrated on the exterior of the reed valve case to ensure a superior seal for the entire intake tract. This crucial modification prevents over-fuelling, particularly during extreme uphill or downhill riding, thus eliminating bogging and rich running. Boyesen continues to supply their renowned carbon membranes for the reed valve system, ensuring top-tier performance and durability.
Electric Power Valve: Precision and Simplicity
The integration of EFI has also enabled a smarter approach to the power valve. Now electronically controlled based on throttle position and engine RPMs, the power valve is auto-calibrating. This eliminates the need for manual adjustments, with the Engine Management System (EMS) automatically calculating the ideal position for the power valve. The result is a beautifully linear and predictable power delivery, regardless of how aggressively the throttle is applied. This translates to a more confidence-inspiring and user-friendly riding experience.
Refined Exhaust System
The exhaust system on the 2023 KTM SX range has been refined for improved functionality. A more compact exhaust header design enhances ground clearance, reducing the risk of damage from deep ruts or external obstacles. The silencer has also received the 'compact treatment', crafted from lightweight aluminium and finished with a premium black coating, adding to the bike's sleek aesthetics and reducing overall weight.
Selectable Engine Maps: Tailor Your Power
The introduction of EFI also opens the door to selectable engine maps, easily accessible via a handlebar-mounted switch. Map 1 offers a standard, more mellow power delivery for smooth and predictable performance, ideal for learning the bike or for less demanding conditions. Map 2, on the other hand, unleashes a more aggressive character, providing immediate throttle response and a crisper, more explosive power output for those seeking maximum performance.
Electric Start: Convenience and Weight Saving
Another significant new feature for the 2023 KTM SX range is the electric start. This convenient system is operated via a newly designed combined Start/Stop switch located on the right side of the handlebar. The starter motor is integrated without an intermediate shaft, contributing to a more compact engine design and saving valuable weight. Further weight savings are achieved through the use of an ultra-lightweight 12.8V 2 Ah Lithium-Ion battery, strategically placed under the seat near the bike's centre of gravity for optimal weight distribution.
The New Contender: KTM 300 SX
The 2023 season sees the exciting debut of the KTM 300 SX, entering the MX Open category as a formidable new option. This powerhouse is designed for racers who demand maximum power with minimal weight. Offering simplicity and low maintenance, the 300 SX boasts massive power output. With an astonishing overall dry weight of just 99.4 kg (219.1 lbs), this new 300 SX engine sets a new benchmark for power-to-weight ratios. It's engineered to deliver more torque than any previous KTM 2-stroke engine, all while retaining that characteristic high-revving, lightweight 2-stroke character that riders love.
Comparative Specifications: 2023 KTM SX Range
To help you understand the differences and similarities across the 2023 KTM SX range, here's a comparison of key specifications:
| Feature | 2023 KTM 125 SX | 2023 KTM 250 SX | 2023 KTM 300 SX |
|---|---|---|---|
| Engine Type | Single Cylinder, 2-Stroke | Single Cylinder, 2-Stroke | Single Cylinder, 2-Stroke |
| Displacement | 124.8 cc | 249 cc | 293.2 cc |
| Fuel System | Keihin EFI, 39 mm throttle body | Keihin EFI, 39 mm throttle body | Keihin EFI, 39 mm throttle body |
| Starter | Electric starter / Lithium Ion | Electric starter / Lithium Ion | Electric starter / Lithium Ion |
| Transmission | 6 Gears | 5 Gears | 5 Gears |
| Weight (without fuel), Approx. | 92.4 kg / 203.7 lbs | 99.4 kg / 219.1 lbs | 99.4 kg / 219.1 lbs |
| Tank Capacity, Approx. | 7.2 L / 1.90 gal | 7.2 L / 1.90 gal | 7.2 L / 1.90 gal |
Frequently Asked Questions
Does the KTM SX have electronic fuel injection?
Yes, the 2023 KTM SX range, including the 125 SX, 250 SX, and the new 300 SX, features electronic fuel injection across the board.
What are the main benefits of EFI on the new KTM SX models?
The main benefits include improved throttle response, optimal power delivery in all conditions, easier starting, reduced fuel wastage, and the elimination of the need to manually adjust jetting for different altitudes or temperatures.
Is there a new 300cc model in the 2023 KTM SX line-up?
Yes, KTM has introduced the all-new 300 SX for 2023, offering increased power and torque for the MX Open category.
Does the new KTM SX range have electric start?
Yes, all models in the 2023 KTM SX range are equipped with electric start, powered by a lightweight Lithium-Ion battery.
Can I change the engine characteristics on the 2023 KTM SX?
Yes, the new models feature a map select switch on the handlebar, allowing you to choose between two different engine maps to suit track conditions and rider preference.
Conclusion
The 2023 KTM SX range represents a significant evolution for 2-stroke motocross bikes. With the introduction of electronic fuel injection, electric start, and a host of other carefully considered upgrades, KTM has delivered a package that is not only more powerful and responsive but also more user-friendly and adaptable than ever before. Whether you're a seasoned racer or a passionate enthusiast, these advancements promise an exhilarating and refined riding experience, truly setting a new standard in the class.
If you want to read more articles similar to KTM SX: Fuel Injection Revolutionised, you can visit the Motorcycles category.