im pretty sure its all one in the sameThe rectifier doesn't control voltage, it only converts AC to DC, the voltage regulator limits the volts. I'm not sure if that motor has a separate regulator/rectifier or if they're combined in one unit, but it would be the regulator portion that's not working.
yes contacts are clean, tested with multi meterDid you clean the conacts on the battery? A bad contact would cause the regulator to sense low voltage on the battery side.
Also, verify the voltage with a test meter (dash gauges are not accurate)
yes contacts are clean, tested with multi meter
Yes it is a water cooled rectifier/ regulatorim pretty sure its all one in the same