This is the only one I will recommend. http://dynamoregulators.com/dvr2.php

It will continue to work even when the volts drop low (Unlike the other makes that I've had trouble with). A one man band who will stand by his product

Ron

email (option): ronpier@talk21.com

Most WDG3L owners would be happier with a voltage regulator that works without a working generator!

I would also recommend the DVR regulator. I have fitted them to several bikes including the M20 and found them faultless.