2008 Yamaha Motorsports Grizzly 450 Auto. 4x4 Special Edition Owners Manual - Page 110
2008 Yamaha Motorsports Grizzly 450 Auto. 4x4 Special Edition Manual
Page 110 highlights
3. Remove the spark plug as shown, with the spark plug wrench included in the owner's tool kit. NOTE: If the spark plug shows a distinctly different color, the engine could be operating improperly. Do not attempt to diagnose such problems yourself. Instead, have a Yamaha dealer check the ATV. 2. Check the spark plug for electrode erosion and excessive carbon or other deposits, and replace it if necessary. Specified spark plug: NGK/DR8EA To install the spark plug 1. Measure the spark plug gap with a wire thickness gauge and, if necessary, adjust the gap to specification. Spark plug gap: 0.6-0.7 mm (0.024-0.028 in) 1. Spark plug wrench 8 To check the spark plug 1. Check that the porcelain insulator around the center electrode of the spark plug is a medium-to-light tan (the ideal color when the ATV is ridden normally). 8-15