Changing the spark plugs on your motorcycle is vital to the overall service routine and should be done regularly. Yamaha recommends replacing the plugs at 7000 mi (11,000 km) and subsequently every 6000mi/10,000km). Since I am on the racetrack quite often in the summer months, I chose to replace my sparks at least once a season. If you are riding the bike on the street only, you can most likely get away with changing the sparks at the suggested mileage intervals (vs. yearly)  The manufacturer model for the spark plug is NGK CR8E, and the recommended spark plug gap is 0.7 to 0.8mm (0.028-0.031 in). When installing the plugs, the…