Yamaha YZ 250 – CG23C/1SS6 Tire Pressure, Oil Type & Fluid Specs

The Engineering Legacy of the CG23C

The 2014 Yamaha YZ 250 (CG23C/1SS6) holds a unique position in motocross history as a surviving titan of the two-stroke era. While competitors pivoted exclusively to four-strokes, Yamaha continued to refine this platform. A key engineering highlight of the 2014 model is its industry-leading KYB® Speed-Sensitive System (SSS) suspension. This was one of the first production systems to use piston speed—rather than just position—to determine damping force, providing a level of control and bottoming resistance that remains a benchmark for motocross performance even a decade later.

Technical Performance & Power Delivery

At the heart of the CG23C is the legendary 249cc reed-valve inducted engine. Known for its explosive yet manageable powerband, the 2014 iteration benefited from years of porting refinement. The lightweight aluminum frame, introduced in the mid-2000s and subtly updated for this generation, offers a perfect balance of rigidity and flex, ensuring the bike remains one of the most agile machines in the 250cc class.

Maintenance Essentials

Maintaining the YZ 250 is straightforward, which is a primary reason for its enduring popularity among privateer racers and enthusiasts. To ensure peak performance, follow these specific technical requirements:

• Engine Lubrication: The gearbox requires 0.75 Liters of SAE 10W-30 oil. Ensure the oil meets API SG standards or higher and carries the JASO MA certification to prevent clutch slippage.
• Ignition: The NGK BR8EG spark plug is the factory-specified component. Regular inspection is critical to prevent fouling, especially if the carburetor jetting is not perfectly tuned for your altitude.
• Tire Pressure: For standard motocross conditions, both the front (80/100-21) and rear (110/90-19) tires should be set to 1.0 bar (approximately 15 psi). Adjustments may be necessary based on track hardness.

Frequently Asked Questions