8-9EBU00286Spark plug inspectionThe spark plug is an important engine compo-nent and is easy to inspect. The condition of thespark plug can indicate the condition of theengine.For example, a very white center electrodeporcelain color could indicate an intake air leakor carburetion problem for that cylinder. Do notattempt to diagnose such problems yourself.Instead, take the machine to a Yamaha dealer.You should periodically remove and inspect thespark plug because heat and deposits will causethe spark plug to slowly break down and erode.If electrode erosion becomes excessive, youshould replace the spark plug with one of theproper type.Before installing the spark plug, measure theelectrode gap with a feeler gauge and adjust tospecification.a. Spark plug gapaStandard spark plug:CR7HS (NGK)Spark plug gap:0.6 ~ 0.7 mm (0.024 ~ 0.028 in)
