Quick Analysis
KTM 50 SX
9.5 pts
Unweighted: 4 advantages
EnginePerformanceDimensionsBrakesTyresFeaturesOther
KTM RC 390
27.5 pts
Unweighted: 23 advantages
EnginePerformanceDimensionsBrakesTyresFeaturesOther
| Specification | ||
|---|---|---|
Engine Specifications |
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| Cooling System | — | Liquid cooling. Curved radiator with fans for better heat management |
| Displacement | 49.9 cc | 373.27 cc |
| Engine Type | 1-cylinder, 2-stroke engine | Single Cylinder, Liquid Cooled, DOHC, FI Engine |
| Power | 5.3 bhp @ 11500 rpm | 43.5 PS @ 9000 rpm |
| Torque | 5.2 Nm @ 7500 rpm | 37 Nm @ 7000 rpm |
Performance & Efficiency |
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| Fuel Tank Capacity | 2.3 L | 13.7 L |
| Mileage | 30 kmpl | 29 kmpl |
Dimensions & Weight |
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| Kerb Weight | 41 kg | 172 |
| Seat Height | 653 mm | 835 |
Brakes & Suspension |
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| ABS | — | Dual Channel ABS |
| Front Brake | Disc 160 mm | 320 mm Disc with Radially mounted calliper |
| Front Suspension | XACT 35 WP Upside-Down fork, Ø 35 mm | WP APEX USD forks, 43 mm diameter |
| Rear Brake | Disc 160 mm | 230 mm Disc with Floating calliper |
| Rear Suspension | XACT WP mono shock | WP APEX Monoshock, 10 step adjustable |
Tyres & Wheels |
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| Front Tyre | 60/100 - 12 | 110/70 - 17 |
| Rear Tyre | 2.75 - 10 | 150/60 - 17 |
| Tyre Type | Tubed | Tubeless |
| Wheel Type | Spoke | Alloy |
Features & Technology |
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| Headlight | — | LED Headlamp |
Other Specifications |
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| Battery | — | 12 V, 8 AH MF battery |
| Bike Image 1 | — | https://motoautiv.com/wp-content/uploads/2025/12/GP-Edition-Blue.avif |
| Bike Image 2 | — | https://motoautiv.com/wp-content/uploads/2025/12/Orange.avif |
| Bike Image 3 | — | https://motoautiv.com/wp-content/uploads/2025/12/GP-Edition-Orange.avif |
| Cluster | — | TFT Multifunction display |
| Color Options | Electronic Orange | Orange | #FF5A00 Blue | #1F3F8B GP Edition Blue | #1F3F8B, #FF5A00 GP Edition Orange | #FF5A00, #1F3F8B |
| Cons | High Maintenance: As a 2-stroke engine, it requires frequent servicing and tuning. Small Fuel Tank: Limited capacity means more frequent refills. Kick-Start Only: No electric start, which can be tricky for very young riders. Limited Power for Older Kids: The 50cc engine may not be enough as the rider grows or becomes more skilled. Sensitive to Tuning: Owners report issues like fouling spark plugs or needing to frequently re-jet the carb: “Used to run great … then started fowling plugs … Moved to a 95 main jet … About 15 kph slower …” Parts Cost & Availability: As a race‑oriented bike, some parts can be expensive or harder to source for older models. | Heat Buildup: The single-cylinder engine can produce noticeable heat in heavy traffic or slow-moving city rides. Harsh Ride at Low Speeds: Stiff sport suspension can make daily commuting rough on bumpy or uneven roads. Aggressive Riding Posture: The forward-leaning position can be fatiguing for longer rides or casual commuting. Fuel Efficiency: The bike’s performance comes at a cost — real-world mileage is moderate when ridden aggressively. Maintenance Costs: Premium parts and periodic services (especially for the high-performance components) can be more expensive compared to typical middleweight bikes. Limited Comfort for Pillion: The rear seat is compact and not very comfortable for longer pillion rides. |
| Detailed Overview | The KTM 50 SX is a purpose-built mini motocross bike, tailored primarily for very young and beginner racers who want to get a genuine motocross experience without jumping straight to bigger bikes. It’s more than just a “toy” — KTM has packed serious race-bike DNA into this 50cc model, making it a standout choice for youth motocross training and competitive racing. At the heart of the 50 SX is a 49.9 cc single-cylinder 2-stroke engine, which delivers a punchy yet manageable power output. According to KTM’s specs, this engine is paired with a centrifugal automatic clutch, meaning there’s no manual clutch lever to worry about — the clutch engages automatically, which is ideal for young riders still building coordination and confidence. The engine uses a Seletra 2p D36 system for fuel delivery (on some models), which helps in precise tuning and reliable performance. KTM has thoughtfully designed the chassis for both strength and agility. The frame is made from chromoly steel, which keeps it light but sturdy. The overall design ensures that the bike is highly maneuverable, making it easier for young riders to learn balance and control on a real race-ready structure. The 50 SX isn’t just about motor and frame — it comes with serious suspension too: a WP XACT 35 mm upside-down fork at the front and a WP mono‑shock at the rear.The front suspension travel is around 200 mm and the rear is close to 190 mm, giving enough give for track bumps and jumps. In terms of ergonomics, the seat height is just 653 mm, making it very accessible for younger riders. Ground clearance is around 233 mm, giving the bike enough space to handle uneven terrain without scraping too much.The fuel tank capacity is modest — 2.3 liters — but that’s more than enough for short motocross sessions that young riders typically do. For braking, KTM hasn’t compromised: the 50 SX is equipped with disc brakes both front and rear, each 160 mm in size. This provides good stopping power and control, which is very important for safety and learning advanced braking techniques. On the wheels front, the bike uses spoke wheels, keeping things light and rugged for off-road racing. Despite its small size, the 50 SX is very race-focused. The frame has been redesigned to mimic the flex and rigidity characteristics of full-size MX bikes. The new frame also comes with frame protectors, which help reduce damage in case of falls — a common occurrence when young riders are learning. The handlebars are lightweight aluminum, with a bend that suits smaller riders, and the footpegs are designed to give a solid grip even when things get muddy or rough. KTM also includes power-reduction kits in its parts catalog for the 50 SX. These kits let parents or coaches limit the power output while the rider is still learning, which is a smart way to scale the bike’s performance to the rider’s ability — and once they’re better, the full power can be unlocked. When it comes to reliability, the 50 SX has a liquid cooling system for better thermal management. The engine’s central crankshaft design helps in keeping the mass well-balanced, which contributes to smoother handling. As for maintenance, like all 2-stroke motorcycles, it does need regular care — but KTM has made key parts (like the clutch) durable, using a reinforced clutch basket for longevity. Overall, the KTM 50 SX is a very well-engineered youth motocross bike that brings real race performance to younger riders. It balances power, weight, and control in a way that helps beginners grow into serious racers. Whether for track training, competitive racing, or just building early riding skills, it’s absolutely one of the top choices in the mini-moto world. | The KTM RC 390 is a fully faired motorcycle built around a 373cc, single-cylinder, liquid-cooled engine. This engine produces close to 43 bhp and around 37 Nm of torque, and it is paired with a six-speed gearbox. The power delivery is spread across the rev range, with noticeable strength in the mid and top end, which becomes useful during highway riding and quick overtakes. The bike uses a ride-by-wire throttle system, which manages throttle input electronically, and it also comes with a slipper clutch that helps reduce sudden rear wheel movement during aggressive downshifts. The motorcycle is based on a steel trellis frame, which is designed to keep the weight low while maintaining structural strength. It is equipped with upside-down front forks from WP and a rear monoshock, both of which are tuned to handle higher speeds and cornering stability. The braking setup includes a large front disc and a rear disc, supported by dual-channel ABS. The ABS system also offers a Supermoto mode, which allows the rear ABS to be disengaged while keeping the front active. The bike rides on 17-inch alloy wheels fitted with tubeless tyres. In terms of design, the RC 390 features a fully faired body with a front section that includes a single LED headlamp and integrated indicators. The fairing is shaped to improve airflow around the rider and the engine area. The windscreen is slightly raised to provide some level of wind protection at higher speeds. The seat is split into two sections, with a slightly elevated rear portion, and the fuel tank is shaped to allow the rider to grip it while riding. The overall layout gives the bike a compact and focused appearance. The feature list includes a TFT display that shows information such as speed, gear position, fuel level, and trip data. It also supports smartphone connectivity for basic functions. Other electronic features include traction control, which helps manage wheel spin under acceleration. The bike has a fuel tank capacity of around 13.7 litres, and the kerb weight is approximately 172 kg. The seat height is around 824 mm, which affects how easily riders can place their feet on the ground. The riding position is set up with clip-on handlebars and rear-set footpegs, which creates a forward-leaning posture. This setup changes how the rider interacts with the bike, especially during longer rides or slow-moving traffic. Overall, the KTM RC 390 combines its engine, chassis, and electronic features into a package that is designed to deliver a certain type of riding experience, defined largely by its specifications and mechanical setup. |
| Expert Review | MotoAutiv Team | The KTM RC 390 is designed with a strong focus on performance and track-style riding, which is clear from its sharp fully faired design and aggressive riding posture. The low clip-on handlebars and rear-set footpegs place the rider in a forward-leaning position, offering better control at higher speeds but making slow city rides feel a bit demanding. Its 373cc single-cylinder engine delivers quick and energetic acceleration, especially in the mid and top range, and responds well to throttle inputs during overtakes or highway riding. The six-speed gearbox, along with a slipper clutch, helps in smoother shifts and better control while downshifting. Handling is one of its key strengths, with the bike feeling stable in corners and composed at higher speeds, supported by a lightweight frame and well-tuned suspension. Braking is predictable and confidence-inspiring, with disc brakes and dual-channel ABS adding to safety. It also comes with modern features like a TFT display and ride-by-wire throttle, though the overall setup leans more towards performance than everyday comfort, with a firm seat and committed riding position., 4.2, MotoAutiv Team |
| FAQ (Manual Override) | Q: What is the engine capacity of the KTM 50 SX? A: It has a 49.9 cc 2-stroke engine. Q: What kind of transmission does it use? A: The KTM 50 SX has a single-speed automatic transmission. Q: How is the KTM 50 SX started? A: It uses a kick-start. Q: Does it have a clutch? A: Yes — a centrifugal (adjustable) clutch, so the rider doesn’t have to use a manual clutch lever. Q: What is the fuel tank capacity? A: The fuel tank capacity is 2.3 litres. Q: What is the seat height? A: The seat height is 653 mm. Q: What is the weight of the bike? A: The dry (or “without fuel”) weight is about 43.5 kg for recent models. Q: What kind of suspension does the KTM 50 SX use? A: It comes with WP XACT suspension — a 35 mm upside-down fork in the front and a WP mono-shock at the rear. Q: What brakes does it have? A: It has disc brakes both at the front and rear, each 160 mm. Q: What power does the KTM 50 SX produce? A: The KTM 50 SX produces around 5.3–5.4 PS at ~11,500 rpm. Q: Is the KTM 50 SX road legal? A: No — it's designed for off-road / motocross use, not for street-legal riding. Q: What kind of clutch does it have for young riders? A: It uses a centrifugal clutch, which automatically engages at high RPM — good for beginners or young riders who don’t manually operate a clutch. Q: What is the ground clearance? A: The ground clearance is 233 mm. Q: Is there a guarantee or warranty for KTM 50 SX? A: According to specs, it has a 2-year standard warranty. Q: What is the typical maintenance challenge or issue to watch for? A: Some owners report carburetor tuning issues | Q: What is the engine specification of the KTM RC 390? A: The RC 390 is powered by a 373.27 cc single-cylinder, liquid-cooled, DOHC engine. Q: How much power and torque does KTM RC 390 produce? A: KTM RC 390 generates approximately 43.5 PS at 9,000 rpm and 37 Nm of torque at 7,000 rpm. Q: What is the fuel tank capacity and mileage of the RC 390? A: The bike has a 13.7-litre fuel tank. Q: What type of brakes and safety features does the KTM RC 390 come with? A: It features a 320 mm front disc and a 230 mm rear disc, paired with dual-channel ABS and a Supermoto mode for the ABS system. Q: What suspension setup does the RC 390 have? A: It uses WP APEX 43 mm USD forks at the front and a 10-step adjustable WP APEX monoshock at the rear. Q: What is the seat height and kerb weight of the RC 390? A: The seat height is 835 mm and the kerb weight is 172 kg. Q: Does the RC 390 support quick shifting and a slipper clutch? A: Yes, it comes with a slipper and assist clutch to make downshifts smoother and reduce rear-wheel chatter. Q: What electronic rider aids are available on the RC 390? A: The RC 390 offers several aids, including Motorcycle Traction Control (MTC), cornering ABS, and Quickshifter+. Q: What kind of instrument cluster does KTM RC 390 have? A: It features a TFT multifunction display that shows info like speed, rpm, gear position, fuel range, and more. Q: Is the KTM RC 390 suitable for both city riding and weekend rides? A: Yes, it’s designed to be sporty and rider-focused, making it agile enough for city commuting, while its power and handling also make it a capable pick for weekend rides. |
| Fuel System | — | Electronic Fuel Injection |
| Price Variants | | 475000 | GP Edition | 322719 STD | 323068 |
| Pros | Very Lightweight: Makes it easy for young riders to handle and build confidence. Automatic Transmission: The centrifugal clutch and automatic gearbox simplify riding for beginners. Adjustable Suspension: High-quality WP fork and shock can be tuned to rider weight and track conditions. Racing‑Oriented Build: Frame and components are derived from KTM’s full-size SX range, giving a race-ready feel. Power-Reduction Kits Available: Helps beginners by limiting power until they’re ready for more. Good Cooling: Liquid cooling ensures the engine stays healthy even under hard off‑road use. Tool-Free Adjustability: Seat height, suspension, and other parts can be adjusted without special tools. | High Power for Its Class: With a 373cc single-cylinder engine, the RC 390 delivers blistering performance and is one of the most powerful in its segment. Aggressive Sport Styling: Fully-faired design, sharp lines, and MotoGP-inspired graphics make it visually striking. Premium Components: Equipped with WP suspension, a slipper/assist clutch, and a responsive quickshifter, giving a premium feel at this displacement. Modern Electronics: Features like Traction Control (MTC), cornering ABS, ride-by-wire throttle, and Quickshifter+ boost both safety and performance. Excellent Braking: Strong braking performance using a 320 mm front disc and dual-channel ABS ensures high safety. TFT Instrument Cluster: A full-color display provides essential information and adds a modern touch to the cockpit. Excellent Handling: Lightweight frame and sporty geometry result in agile, confidence-inspiring cornering and performance. |
| Starter | — | Self Start Only |
| Transmission | Manual | 6 Speed Manual |
