2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 320Get this manual

IGNITION SYSTEM

5.Spark plug cap resistance
Remove the spark plug capConnect the pocket tester1k) to the spark plug cap

Check that the spark plug cap has the specified resistanceSpark plug cap resistance: 10 at 20 (68 F) MEETS SPECIFICATION

OUT OF SPECIFICATION

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives