The difference in power output between two 125cc bikes, such as the KTM EXC 125 (15hp) and the KTM SX 125 (30hp), can be attributed to various factors, including the engine design, tuning, and intended purpose of the bike.
Engine Design and Components: The internal components of the engine, such as the cylinder, piston, valves, and intake/exhaust system, play a significant role in determining the power output. Different engine designs and specifications can result in variations in power. For example, the SX 125 might have a higher compression ratio, different valve timing, or a more aggressive camshaft, allowing it to generate more power.
Tuning and Performance Modifications: Manufacturers can tune the engine and make performance modifications to achieve different power outputs within the same engine displacement. The SX 125 is designed for motocross racing, where higher power is often desired, so KTM may have made specific modifications to the engine to optimize its performance for that purpose.
Intended Purpose: The EXC 125 and SX 125 are designed for different riding purposes. The EXC 125 is a model intended for off-road/enduro riding, where a smoother power delivery and better low-end torque might be more important than peak power. On the other hand, the SX 125 is a motocross bike designed for racing, where higher power and aggressive performance are prioritized for acceleration and jumping.
Exhaust System: The design and tuning of the exhaust system can significantly impact the power output. Motocross bikes like the SX 125 often have more free-flowing and performance-oriented exhaust systems compared to enduro bikes like the EXC 125, which may have a more restrictive exhaust for noise reduction and emissions compliance.
It's important to note that these are general factors, and specific details may vary between different bike models and manufacturers. If you're interested in the technical specifications of a particular bike, it's always a good idea to consult the manufacturer's official documentation or contact a KTM dealer for more information.