2010 Yamaha Motorsports Majesty Owners Manual - Page 53

PERIODIC MAINTENANCE AND ADJUSTMENT EAU34172 Checking the spark plug The spark plug is an important engine component, which is easy to check. Since heat and deposits will cause any spark plug to slowly erode, the spark plug should be removed and checked in accordance with the periodic maintenance and lubrication chart. In addition, the condition of the spark plug can reveal the condition of the engine. To remove the spark plug 1. Open the rider seat. (See page 4-12.) 2. Pull up the storage compartment mat, and then remove the spark plug cover by removing the screws. 2 3 1 2 3 1. Storage compartment mat 2. Spark plug cover 3. Screw 1. Spark plug wrench 1 4 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 vehicle is ridden normally). TIP 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 vehicle. 2. Check the spark plug for electrode erosion and excessive carbon or other deposits, and replace 5 6 7 8 9 3. Remove the spark plug cap. 1 1. Spark plug cap 4. Remove the spark plug as shown, with the spark plug wrench included in the owner's tool kit. 7-12