I have a charging issue with my 99 Duc St4. I think I have it, but am wondering ???? I get only 11.7 V at the Battery when running and 12.2 when its not? After a 5-10 minute ride the Battery Voltage dropped .24 Volts. I am guessing/assumming that thie is aht rectifier draining the battery ??? Any extra input would be apprectiated before I replace the Rectifier. Thnx.