What Can Cause a MC Stator, Regulator Rectifier to Go Bad? the number one reason is heat. as per over heated engine oil due to detonation. Tip: see n how v-strom got 11.3:1 CR, its a good idea to always use regular automotive grade fuel with the highest AKI #. for example, i use 91 or higher R+M/2 octane fuel and, ive never had a Stator, regulator rectifier problem so far with 85,000 miles showing on the clock.