Quick Analysis
KTM 50 SX
9.0 pts
Unweighted: 5 advantages
EnginePerformanceDimensionsBrakesTyresFeaturesOther
Aprilia SR 125
28.0 pts
Unweighted: 20 advantages
EnginePerformanceDimensionsBrakesTyresFeaturesOther
| Specification | ||
|---|---|---|
Engine Specifications |
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| Cooling System | — | Air-cooled |
| Displacement | 49.9 cc | 124.45 cc |
| Engine Type | 1-cylinder, 2-stroke engine | Single-cylinder, 4-stroke, SOHC, 3-valve |
| Power | 5.3 bhp @ 11500 rpm | 10.11 PS @ 7300 rpm |
| Torque | 5.2 Nm @ 7500 rpm | 10.33 Nm @ 5500 rpm |
Performance & Efficiency |
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| Fuel Tank Capacity | 2.3 L | 6 litres |
| Mileage | 30 kmpl | 40 kmpl |
Dimensions & Weight |
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| Kerb Weight | 41 kg | 118 kg |
| Seat Height | 653 mm | 780 mm |
Brakes & Suspension |
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| Front Brake | Disc 160 mm | Disc (220 mm) |
| Front Suspension | XACT 35 WP Upside-Down fork, Ø 35 mm | Telescopic fork |
| Rear Brake | Disc 160 mm | Drum (140 mm) |
| Rear Suspension | XACT WP mono shock | Mono-shock / Hydraulic Shock absorber |
Tyres & Wheels |
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| Front Tyre | 60/100 - 12 | 120/70-R14 |
| Rear Tyre | 2.75 - 10 | 120/70-R14 |
| Tyre Type | Tubed | Tubeless |
| Wheel Type | Spoke | Alloy |
Features & Technology |
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| Headlight | — | LED |
Other Specifications |
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| Battery | — | 12V / 5 Ah |
| Bike Image 1 | — | https://motoautiv.com/wp-content/uploads/2025/12/sr125mattblack.webp |
| Cluster | — | Fully digital instrument cluster |
| Color Options | Electronic Orange | Aprilia Black Street Grey Opalescent Light |
| 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. | More expensive than many 125cc scooters, making it a premium purchase. Under-seat storage is smaller than what some rivals offer. Torque and overall performance may feel limited for riders who often travel with a pillion or heavy luggage. Suspension can feel slightly firm for some riders, especially on very bad roads. Service network and parts availability may not be as widespread as mass-market brands. |
| 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 Aprilia SR GT 125 is one of those scooters that immediately feels different the moment you get on it. Instead of behaving like a typical city commuter, it carries the attitude of a lightweight adventure scooter, and that personality starts with its compact but sophisticated 125 cc i-get engine. This single-cylinder motor uses liquid cooling and a four-valve head, which means it breathes freely, runs cooler, and maintains performance even when the roads ahead are busy or slightly demanding. With around 15 horsepower produced at fairly high rpm, the scooter likes to be ridden with a bit of spirit. It doesn’t explode off the line, but it builds speed in a smooth, confident manner, especially when merging into faster traffic. The 12 Nm of torque comes in at mid-range, so in everyday riding the scooter feels responsive without needing to twist the throttle aggressively. Because it uses a CVT transmission, power delivery stays seamless. You just twist and go — making your way through city traffic without a second thought about gears. Even slow-speed maneuvering feels clean, thanks in part to the engine’s start-stop system, which cuts the engine at idle and brings it back to life the moment you twist the throttle. This not only saves fuel, but also makes the scooter feel lively and modern. Aprilia has built the SR GT 125 around a strong double-cradle steel frame, and that chassis gives it a planted feel on the road. Where many scooters tend to bounce or feel vague on broken surfaces, this one feels much more composed. The front end uses a 33 mm telescopic fork with generous travel, and the rear relies on twin shock absorbers with preload adjustment. Together, they soak up rough surfaces without making the rider feel disconnected. Riding over potholes or uneven patches doesn’t rattle the scooter; instead, it delivers a gentle, controlled movement that makes the overall ride surprisingly comfortable for something this sporty. Braking performance follows the same philosophy of confidence and control. Up front, there’s a large 260 mm disc, and the rear gets a 220 mm disc as well. Combined braking ensures that even less experienced riders get a balanced stop without grabbing too much front brake by mistake. In real-world use, the brakes feel progressive and strong — enough to inspire trust during sudden slow-downs, especially in crowded urban conditions. Dimensions also play a role in how this scooter behaves. Its wheelbase provides stability during faster stretches, yet the overall size keeps it agile in tight lanes. The seat height sits just under 800 mm, which means most riders can comfortably place a foot down at signals. The 9-litre fuel tank is larger than what most scooters offer, so you don’t need to refuel frequently — something daily commuters will appreciate. A big part of the SR GT 125’s personality comes from its tyres. With a 110/80-14 tyre at the front and a 130/70-13 at the rear, the scooter gets a slightly rugged stance while also benefiting from better grip and cornering feel. These wider tyres add stability when leaning through curves or navigating slippery monsoon roads. Alloy wheels help keep things light and responsive, making the scooter feel nimble without compromising ride comfort. On the features front, it includes fuel injection, an electric starter, and a modern instrument cluster that gives clear information without clutter. Everything is laid out to focus on real usability — nothing flashy for the sake of it, just features that make everyday ownership effortless. The seating is comfortable, the ergonomics encourage an upright, confident riding posture, and the overall build quality hints at durability. In real riding, the SR GT 125 feels like a scooter that wants to do a bit more than the typical city hop. It handles daily commutes with ease but doesn’t shy away from slightly longer rides or patchy roads. It’s the kind of machine that suits a rider who enjoys a little adventure in everyday life — someone who wants refinement, stability, and the feel of a well-engineered scooter rather than a basic runabout. It strikes a balance between practicality and fun, making it not just a commuter tool but a companion that engages the rider every time the road twists or roughens. |
| Expert Review | MotoAutiv Team | 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 mileage? A: The mileage is around 38–42 kmpl in real-world riding. Q: What is the engine capacity of the Aprilia SR GT 125? A: The engine capacity is 125 cc. Q: How much power does the SR GT 125 produce? A: It produces around 15 hp. Q: What is the torque output? A: The torque output is 12 Nm. Q: Does the Aprilia SR GT 125 have liquid cooling? A: Yes, it uses a liquid-cooled engine. Q: Is ABS available on the SR GT 125? A: It comes with a combined braking system (CBS), not ABS. Q: What is the seat height? A: The seat height is around 799 mm. Q: What is the fuel tank capacity? A: The fuel tank capacity is 9 litres. Q: Is the suspension suitable for rough roads? A: Yes, the long-travel suspension handles uneven roads confidently. Q: What type of tyres does it use? A: It uses a 110/80-14 front tyre and a 130/70-13 rear tyre. |
| Fuel System | — | Fuel-injected |
| Price Variants | | 475000 | 377155 |
| 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. | Sporty and premium design that stands out compared to regular 125cc scooters. Strong handling with a more motorcycle-like feel, giving confidence in corners and during quick lane changes. Comfortable riding posture with good ergonomics for both short commutes and longer weekend rides. Smooth and responsive engine thanks to liquid cooling and fuel injection. Disc brakes at both ends with CBS offer stable and predictable braking performance. Good suspension travel that handles rough city roads better than most scooters in this segment. Alloy wheels and wider tyres provide excellent grip and stability. |
| Starter | — | Kick + Self-start |
| Transmission | Manual | Automatic |
