**KTM 250, 450, and 525 SX/MXC/EXC Engines: A Technical Overview**

Introduced in 2004, the KTM 250, 450, and 525 SX/MXC/EXC models represented a significant advancement in off-road motorcycle technology. These high-performance machines were powered by cutting-edge single-cylinder engines that delivered exceptional power and reliability.

**Engine Design and Architecture**

The heart of these KTMs was their lightweight, liquid-cooled engines. Utilizing a four-valve, single-overhead-camshaft (SOHC) design, these engines optimized valve timing and combustion efficiency, resulting in increased power output. The compact engine architecture allowed for a lower center of gravity, improving handling and stability.

**Cylinder and Piston**

The cylinders featured a nickel-silicon-carbide (Ni-SiC) coating, enhancing durability and reducing friction. Coupled with forged aluminum pistons and high-pressure die-cast piston rings, these engines exhibited exceptional longevity and performance.

**Crankshaft and Balancing**

The robust crankshaft played a crucial role in engine reliability. High-grade materials and precision engineering ensured minimal vibration and smooth power delivery. The use of a lateral balancing shaft effectively compensated for inherent engine vibrations, enhancing rider comfort and reducing fatigue.

**Ignition and Fuel Systems**

Electronic fuel injection (EFI) with dual injectors precisely controlled air-fuel mixtures across the entire rev range, providing optimal combustion. The advanced ignition system utilized a programmable ignition map to optimize spark timing for improved power and fuel efficiency.

**Cooling System**

The liquid-cooling system utilized a thermostatically controlled water pump to maintain optimal engine temperatures. The radiator was positioned strategically to maximize airflow and prevent overheating, ensuring consistent performance even under demanding conditions.

**Transmission and Clutch**

The six-speed transmission provided a wide range of gear ratios, allowing riders to adapt to varying terrain and riding styles. The multi-plate wet clutch engaged smoothly and delivered precise control, enhancing rider confidence and handling.

**Other Features**

* Electric starter for effortless starting
* Compact alternator for reliable power generation
* Lightweight frame and swingarm for improved handling and maneuverability
* Advanced suspension system for exceptional comfort and stability

**Conclusion**

The KTM 250, 450, and 525 SX/MXC/EXC engines were masterpieces of engineering that pushed the boundaries of off-road performance. Their innovative design, advanced technologies, and meticulous attention to detail resulted in motorcycles that delivered exceptional power, reliability, and handling, making them the choice of discerning riders worldwide.

KTM 250,450,525, sx,mxc,exc engine parts book.
Year 2004
This is a fully illustrated parts list with exploded views.
It can be a helpful tool to assist disassembly and assembly.