Yamaha - Cam Gear Engine Timing Component YF1-68641-65-10. Overview. When you're deep into a Yamaha engine, timing is where everything either comes together or falls apart. I've seen engines that just wouldn't run right, and it all traced back to worn timing gears. The Yamaha Cam Gear YF1-68641-65-10 keeps the valve timing in sync so the engine runs smooth and consistent. It's not something you replace often, but when it's needed, it makes a big difference in how the motor performs.. Key Features. • Precise Valve Timing Control - Keeps camshaft rotation synchronized for proper engine operation.. • Yamaha Engineered Fit - Designed to match factory specifications for accurate alignment and engagement.. • Hardened Gear Construction - Built to handle constant internal engine loads and long-term use.. • Supports Smooth Engine Performance - Helps maintain consistent timing for reliable power delivery.. • Direct Replacement Component - Fits in place of the original gear during engine service