2008 Yamaha Motorsports Royal Star Venture S Owners Manual - Page 78
2008 Yamaha Motorsports Royal Star Venture S Manual
Page 78 highlights
PERIODIC MAINTENANCE AND MINOR REPAIR EAU19544 Checking the spark plugs The spark plugs are important engine components, which are easy to check. Since heat and deposits will cause any spark plug to slowly erode, the spark plugs should be removed and checked in accordance with the periodic maintenance and lubrication chart. In addition, the condition of the spark plugs can reveal the condition of the engine. To remove a spark plug 1. Remove the spark plug cap. 3. Check each spark plug for electrode erosion and excessive carbon or other deposits, and replace it if necessary. Specified spark plug: NGK/DPR8EA-9 DENSO/X24EPR-U9 1. Spark plug wrench 7 To check the spark plugs 1. Check that the porcelain insulator around the center electrode on each spark plug is a medium-tolight tan (the ideal color when the vehicle is ridden normally). 2. Check that all spark plugs installed in the engine have the same color. NOTE: If any 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. To install a spark plug 1. Measure the spark plug gap with a wire thickness gauge and, if necessary, adjust the gap to specification. 1. Spark plug cap 1. Spark plug gap 2. Remove the spark plug as shown, with the spark plug wrench included in the owner's tool kit. Spark plug gap: 0.8-0.9 mm (0.031-0.035 in) 7-11