2007 Yamaha Apex Factory Service Manual, Page 19Get this manual

2007 Yamaha Apex Factory Service Manual, Page 19

SPARK PLUGS INSP ADJ SPARK PLUGS 1Remove: Spark plug caps Spark plugs 2Inspect: Electrodes DamagewearReplace the spark plugS
0.031 in) If necessary, clean the spark plugs with spark plug cleanerStandard spark plug: CR9E (NGK) Before installing spark