2002-2006 Yamaha YFR450FAR Service Manual LIT-11616-16-01, Page 330Get this manual
IGNITION SYSTEM Spark plug gap: 0.60.7 mm (0.0240.028 in) CORRECT INCORRECT
Repair or replace the spark plug
4.Ignition spark gap
Disconnect the spark plug cap from the spark plugConnect the dynamic spark tester as shownTurn the main switch to "ON"Check the ignition spark gapCrank the engine by pushing the starter switch, and increase the spark gap until misfiring occursMinimum spark gap: 6.0 mm (0.24 in) OUT OF SPECIFICATION OR NO SPARK