1999-2004 Suzuki King Quad LT-300 300F ATV Factory Service Manual, Page 22Get this manual
PERIODIC MAINTENANCE
ELECTRODE'S CONDITION Check the condition of the electrodeIf it is extremely worn or burnt, replace the spark plugReplace the spark plug if it has broken insulator, damaged threads, etc
I CAUTION I
Check the thread size and reach when replacing the spark plugIf the reach is too short, carbon will be deposited on the screw portion of the spark plug hole and engine damage may result