Yesterday I encountered the same problem. Fortunately I was alert to the possibility thanks to this thread and had the voltmeter punched up...I watched the voltage drop to into the elevens and was able to make it home.

Because I have the special talent of fixing things that aren't broken, I wanted to test the output and health of the alternator before assuming the problem was the regulator/rectifier. Ironically, the most accessible info that I found was on the Cycle Electrics website, manufacturer of our dreaded CE-601 units. The misspelling is part of the correct URL:

http://www.cycleelectricinc.com/Diegnosing%20Alternators.htm

I checked an old automotive shop manual as backup, and it did seem safe to disconnect the 3-pin plug and run the engine. Before doing this, I had charged the battery to 100% capacity.

I got 23-24 VAC on all three legs with the engine idling at 1200 rpm, and none were shorted to ground as indicated by my test light. This was a huge relief to me, because as you know, R&R of the alternator is an engine-out job and not something we in central Oregon (no dealers) like to contemplate. It was then a matter of handing over $150 at the Harley shop for the same unit that Blake put in.

I have yet to enjoy the 'minor fiddling' referred to above but things could have been a lot worse.

The 3-point mount appears to me to be very robust, but what is mounted to those cunning triangular plates is a Cycle Electrics CE-601 with two holes in it, which have been drilled out. One of the three rubber vibration isolators had cracked halfway through, but a spare from my Norton Commando stocks will fit with a fender washer as a shim.

The output of my alternator, if my voltmeter is reporting accurately, sure seems robust...

Steve Black