2008 Arctic Cat 366 ATV Service Manual, Page 97Get this manual
NOTE: Prior to replacing the CDI unit to assure the CDI unit is defective, it is advisable to perform CDI peak voltage test (see Ignition Coil in this section) andor perform continuity test of the wiring harness from the CDI connector to the CDI unit RegulatorRectifier
The regulatorrectifier is located under the front rack and front fenders above the oil coolerTESTING 1Start engine and warm up to normal operating temperatures; then connect multimeter to the battery as follows2Select the DC Voltage position; then connect the red tester lead to the positive battery post and the black tester lead to the negative battery post3Start the engine and slowly increase RPMThe voltage should increase with the engine RPM to maximum of 15.5 DC voltsNOTE: If voltage rises above 15.5 DC volts, the regulator is faulty or battery connection is loose or corrodedClean and tighten battery connections or replace the regulatorrectifierIf voltage does not rise, check Voltage (Charging CoilNo Load) in this sectionIf charging coil voltage is normal, replace the regulatorrectifierKC223