2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 206Get this manual
ELECTRICAL Charging System Testing Flow Chart
Whenever charging system problems are suspected, proceed with the following system check after verifying that all wires are in good condition, connected and not exposed or pinched: Set your voltohm meter to read DC Volts, measure the battery open circuit voltage (see procedure later in chapter)It should be 12.4 volts or moreIs it? Yes
Meter Setting: DC Volts
Remove the battery and properly serviceReinstall the fully charged battery or fully charged shop battery
With the transmission in Neutral, start the engine and increase RPM to between 3000 and 4000Read battery voltage with the multitesterReadings should increase to between 13.0 and 14.6 VDCAre they? No
Meter Setting: DC Amps
Check Key off Current Draw
Perform system "Break Even Amperage" test outlined in this chapterDoes charging occur as specified? No Ohm stator wires, if bad replace stator, if good, continue with alternator output testMeter Setting: AC Volts Disconnect the White wire stator harness connectorUsing multitester, perform an Alternator Output testSee test procedure in this chapterDoes output meet specification?