Yamaha YZ85(D) Owner's Manual

Also see for YZ85( P) /LC: Owner's service manual Owner's service manual Owner's service manual Owner's service manual Owner's manual

Contents

PERIODIC MAINTENANCE AND ADJUSTMENT7-87EAU19613Checking the spark plugThe spark plug is an important enginecomponent, which is easy to check.Since heat and deposits will cause anyspark plug to slowly erode, the sparkplug should be removed and checkedin accordance with the periodic mainte-nance and lubrication chart. In addition,the condition of the spark plug can re-veal the condition of the engine.To remove the spark plug1. Remove the spark plug cap.2. Remove the spark plug as shown,with a spark plug wrench availableat a Yamaha dealer.To check the spark plug1. Check that the porcelain insulatoraround the center electrode of thespark plug is a medium-to-light tan(the ideal color when the vehicle isridden normally).TIPIf the spark plug shows a distinctly dif-ferent color, the engine could be oper-ating improperly. Do not attempt todiagnose such problems yourself. In-stead, have a Yamaha dealer checkthe vehicle.2. Check the spark plug for electrodeerosion and excessive carbon orother deposits, and replace it ifnecessary.3. Measure the spark plug gap with awire thickness gauge and, if nec-essary, adjust the gap to specifica-tion.1. Spark plug cap1. Spark plug wrenchSpecified spark plug:NGK/BR10EG1. Spark plug gapSpark plug gap:0.5–0.6 mm (0.020–0.024 in)U1SN81E0.book Page 8 Tuesday, June 12, 2012 3:17 PM