2004 Yamaha Motorsports Bruin 350 Auto. 4x4 Owners Manual - Page 124
2004 Yamaha Motorsports Bruin 350 Auto. 4x4 Manual
Page 124 highlights
2. Use the spark plug wrench in the owner's tool kit to remove the spark plug as shown. Instead, take the ATV to a Yamaha dealer. You should periodically remove and inspect the spark plug because heat and deposits will cause the spark plug to slowly break down and erode. If electrode erosion becomes excessive, or if carbon and other deposits are excessive, you should replace the spark plug with the specified plug. Specified spark plug: DR8EA (NGK) 1. Spark plug wrench Inspection The spark plug is an important engine component and is easy to inspect. The condition of the spark plug can indicate the condition of the engine. The ideal color on the white insulator around the center electrode is a medium-to-light tan color for an ATV that is being ridden normally. Do not attempt to diagnose such problems yourself. Installation 1. Measure the electrode gap with a wire thickness gauge and, if necessary, adjust the gap to specification. Spark plug gap: 0.6-0.7 mm (0.02-0.03 in) 8-17