2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 356Get this manual
IGNITION SYSTEM
6.Ignition coil resistance
C0NTINUITY
Disconnect the ignition coil connector from the wire harnessConnect the pocket tester1) to the ignition coilTester (+) lead Orange lead terminal Tester () lead Ignition coil base
Check that the primary coil has the specified resistancePrimary coil resistance: 0.180.28 at 20 (68 F)