I Assume this is Negative Earth

[Magista]

Ok my friends...can ya'll verify that this is Negative Earth? *sounds like a Doom rock band*

Another question - Was the '58 A7 originally + Earth? I'm assuming the PO changed it at some point.

The old Lucas rectifier is shot so I'm gonna go DVR2 and convert to 12 volt. I don't mind a 6 volt system but with the way ppl drive around here I want brighter lights.


 

[groily]

Well, the battery neg is connected to earth, certainly!
Whether the dynamo is set for neg earth is another matter.
Not sure if 'export' models might have been neg earth if yours was an export originally (as opposed to a later 'come-over'). Others here will know for sure.
UK models would all have been Pos I'm pretty sure.
A lot of the bikes exported to continental Europe were set to Neg from day 1 - whether by the factory or by the local agents, dunno. The rest of the world preferred it that way.
The choice is yours, but order the new regulator to suit, and then set to the voltage you want, with or without swapping your dynamo internals for finer windings if you want to maintain original cut-in charging speeds and spend a few more $$$.
Many LEDs, if you go that way, will be just as bright at 6 as at 12v, and you don't have to stay with a 30/24W original type low-power globe if that's what's in there, whichever voltage you go for.
Personally, it's 12v every time as bits and batteries are easier to get and the fewer amps wandering around the happier I am.

[Magista]

Thank you. I was 99.9% sure, just needed verification from outside eyes before I bought the DVR2.

Mine is an original export (import for us 'Muricans). I have copies of the papers from Hap.

Without the mods to the dynamo, what is the general cut-in speed? I seem to recall reading somewhere it's around 3k rpm?

[groily]

. . .  what is the general cut-in speed? I seem to recall reading somewhere it's around 3k rpm?

Oh no, far less luckily.
Say c.1000rpm engine to cut in, and say 35mph-ish on standard gearing to 'balance' an original headlamp + tail etc on the ammeter? Bit more throttle at 12v, or 'same' with finer windings.
With LEDs, no load to speak of so all very undemanding on dyn and battery, whether you upgrade or not.

[Magista]

To clarify - 1k with the 12 volt system and no mods to dynamo or 1k with the 6 volt system?

[groily]

Without mods, 6v as original.
Few more revs without mods, 12v.
As original rpm at 12v with mods.
Broadly.
But largely moot if LEDs used, as no loads to speak of.

[Magista]

Thank you for clarifying. I appreciate it.

Much lower cut-in than my CL350. It doesn't start charging until about 3k rpm.

BTW - Just ordered a DVR2 and an LED for the headlight (thanks for the tip).

[muskrat]

G'day Magista.
I would suggest a little heavier earth lead to the frame. May not NEED it but I've found less problems that way.
Cheers

[Joolstacho]

While you're at it Magista, fit an LED headlamp bulb/globe - brilliant (literally).

[Triton Thrasher]

The old Lucas rectifier

Regulator and cut-out, in a control box.  There’s no rectifier.

[Magista]

The old Lucas rectifier

Regulator and cut-out, in a control box.  There’s no rectifier.

Got it. Thank you.

[Magista]

While you're at it Magista, fit an LED headlamp bulb/globe - brilliant (literally).

Absolutely, ordered one yesterday.