2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 334Get this manual
CHARGING SYSTEM ELEC
Start the engine and accelerate to about 3,000 rminCharging voltage: 14 at 1,000 rmin MEETS SPECIFICATION
NOTE: Use fully charged batteryOUT OF SPECIFICATION
EB804012
The charging circuit is not faulty
4.Charging coil resistance
Disconnect the CDI magneto coupler from the wire harnessConnect the pocket tester1) to the charging coilsTester (+) lead White terminal Tester () lead White terminal Tester (+) lead White terminal Tester () lead White terminal OUT OF SPECIFICATION