6V Regulator

[Mark3Cam]

Hey guys and gals, aside from a tiny battery with three caps and a points system on what is likely a 72 350, I have this sad looking regulator. Looking to confirm the bike is indeed six volt as she is a bit of a basket case. Take a look at the pics and let me know your thoughts. Tips to identify a 6V system would be appreciated. Looks like Iam sporting a Kawasaki coil

[Bevel bob]

I would have assumed its 12v. What makes you think its 6v?.

[Mark3Cam]

I guess this general confusion, of all the bits and pieces she came with...and that tiny battery. Should I be keying in on the engine vintage? 1972 350’s where 12v systems?

[Dan C]

Check the bulbs and horn, the bulbs will be marked either 6v or 12v and most horns are marked as well. It will give you a clue but be aware that someone could have put 12v stuff on a 6v system and vice versa.....seen that before....
As a general rule all Italian singles were 6v but many have been converted to 12v. The regulator and coil don't look original so conversion is quite possible.


Cheers
Dan

[Mark3Cam]

Will the number of wires from the alternator indicate a 12 or 6v system? Three for a 6v and two for a 12v?

[veloduke]

The 'regulator' looks like a generic bridge rectifier coupled to a zener diode mounted on a heatsink extrusion that you can buy from RS.
It's crude and inefficient, and was fitted to British Bikes in the '60's.
You can get better looking and better working rectifier/regulators from bike stores or off fleabay.
Can't be sure about a definitive identification of the alternator, but I have 3 wire alternators on two of my bikes, and use the yellow wires to feed the rectifier/regulator. They both run 12V electrics, and need about 2000rpm to charge the battery, so they are porbably 6V alternators.
I'm not saying this is the best thing to do, but it works for me.
If you're feeling flush with money, the an Electrex World system works well.

Good luck

[Dan C]

Will the number of wires from the alternator indicate a 12 or 6v system? Three for a 6v and two for a 12v?

Being a coil ignition bike there should be 3 wires coming from the alternator. 1 red and 2 yellow. The number of wires does not determine the voltage.
I'm not an expert on this. Ducwiz (Hans) will be able to give you a definitive answer when he gets around to checking in.
But for what its worth my understanding is that the alternator doesn't determine the voltage, the regulator does. All the alternator does is generate wattage which feeds the regulator. Depending on the regulator output you have either a 6v or a 12v system. If the bike is running you can test the output at the battery with a voltmeter, you'll get either ~7 volts (6v system) or ~13 volts (12v system)

Check out this thread started by Ducwiz
viewtopic.php?f=3&t=2894
There are also plenty of other similar threads, it might be worth your while to have a look for them.


Cheers
Dan

[Ventodue]

<snip> a tiny battery with three caps ...

= 6 volts.

1972 350’s where 12v systems?

Nope, not ex-factory.

Ciao

Craig

[veloduke]

the alternator doesn't determine the voltage

Partly does, in as much as an alternator designed for a 12V system will reach that voltage at a lower engine rpm.
That is, for any given rpm it will generate more voltage than an alternator designed for a 6V system.
That is why on my bike with the alternator designed for 6V electrics has to spin a little faster to generate enough voltage for the 12V regulator I have fitted.

[Mark3Cam]

Thanks for all the input guys. So a 6V battery is not a conclusive evidence of a 6V system and neither is the wire count from the alternator but a 12v system could operate on a 6V battery....lol. Is there anything straight forward on this lovely machines?! I guess at some point the mysteries will give way to working options. Not super knowledgeable or experience with working on electrical systems but such a relatively simple bike seems a good place to start. I just want to make the correct purchases when it’s time to start on the electrical. Seems like a common thing to stay away from the original Italian electrics in favor of some after market or Japanese fair?