If you use a Harley regulator, it has to be matched to the generator which was on the bike. HD 65 and 65A generators were rated at 10 amps while the 61 was rated at 15 amps. Mid sixties thru ’77 or so kick start Sportster XLCH bikes used the 10 amp system with a small Bosch mechanical regulator. If you want to stick with a mechanical instead of electronic regulator, the small Bosch is probably the one to use. They aren’t very big and I can post a photo or some measurements of one tomorrow so you can see the size of them.

Here’s a small 12V Bosch style regulator but I really doubt if it’s made in Germany for the selling price.

http://www.ebay.com/itm/74511-65-12v-Me … 1177519752

I sent you a PM.

I’m not sure what a ‘Type A’ generator is. Don’t believe I’ve heard that before. I usually hear them referred to as shunt wound or three brush or something. I do know there is a difference in how they work though. Some use permanent magnets while others use a separate 12 volt power source or any residual magnetism left in them to get themselves energised. All I know about this HD system is it kept the small battery charged and the lights bright at night!

I took the cover off the HD regulator and could only see two relays and 12V 10A stamped on the end. My chicken scratch wiring diagram is AWOL but I do remember the generator has an ‘A’ and ‘F’ terminals on it which hook up to the regulator. Another wire goes from the regulator to the battery or key switch. This style regulator has to be grounded to as it has rubber mounts and also needs to be polarized before it will work properly. I’m kinda wishing I had a generator equipped Big Twin or RD around so I could try this one out.

Here’s the overall measurements.

Height……4 1/2"

Width……2 5/8"

Depth……3"