Px wiring

[phattanglo]

So I'm slowly but surely getting on with my scoot build and I would value a bit of technical advice please.
Not having a starter motor fitted, I've dispensed with the wiring for it. I am a bit of a minimalist and I wondered if everything electrical including the horn will run directly from the regulator.
If this is the case it occurred to me I could dispense with the battery as well.
Could anyone please confirm if this is correct.
It's a 2012 PX125.

Just as an update I've just read that the battery acts as a buffer to prevent damage to the regulator could anyone confirm if this is the case?

Also my son at some point is going to be re-building his PX200 and when he does he's considering converting to full wave electrics.

He understands that the horn needs changing for a DC version and the rectifier for a different type but he's not sure about the indicator unit, does that also need changing?

[del]

Hello. Sorry I didn't see your message earlier. I did that to mine. I fitted an AC only regulator. I left off the wire which goes to the horn and starter circuit. A five pin one and left the red wire waving in the breeze.
the horn will need to be changed for an AC one. A simple job. the horn has 2 yellow wires. one goes to the button. the other one I ran a 6 inch cable with spade connectors up to the grey wire which went to the Starter interlock relay which I removed.

If your stuck I can go look at my wiring diagram in my Haynes Manual which I updated. Another reason for junking the battery for me was it's given me room for a decent toolkit. all I have in the glove compartment is a plug spanner and a couple of spark plugs. 

[del]

UPDATE: I have looked at my wiring diagram and I shall explain everything as someone else in the World may want to do it.

First the reason. I have a Euro 3 PX125E. It starts second kick, It's a little Engine and I like to keep everything as simple as possible.
I want to fit a bigger cylinder kit.

Problems:

The starter motor is heavy and is right in the way of the Carburetor mixture screw.

The Battery had leaked acid all over the spare tyre, It's heavy and it's sole purpose in life is the starter motor circuit and horn.
I have no interest in fitting 12V DC powered accessories, LED lights etc. (The Television can stay indoors).

The toothed ring on the flywheel will hit the cooling fins on the bottom of the Aftermarket Barrel when fitted. (More hassle)

I fitted a SIP speedo and wired it up as per the AC wiring diagram. It works fine.

The Indicators and lights all run off the AC circuit from the regulator so engine off, Lights off.
The regulator will work without the battery but I've been told it will overheat and pack up in the night when I'm 100 miles from home.

The space occupied by the battery could be used to store a decent tool kit hidden away from thieving Gits who may look inside my glove box for anything worth stealing.

Solution:

Disconnect the Battery. put it on the Bench. Wire up a 6V radio to it and blow it up. (No Music for Derek).

Flywheel off. put it on a shallow spacer so starting ring is clear of the bench. With a hammer and chisel tap the ring off. no need for heating, Grinding or dipping in Holy water. it will come off easily.

Remove starter Motor. 

MOST IMPORTANT! Block the hole in the casing otherwise the the cooling air to the engine won't flow. I temporarily used a ball of rag and a cable tie round the studs to hold it in place. (It will still be there in 10 years time).

replace regulator with a three pin one. the red wire won't have anywhere to go but it's redundant. Fit wires left to right as follows. G- green and grey. G- blue wire. Earth- black wire.

remove horn casting. replace the horn with an AC one.

One yellow wire goes to the horn button. Connect that to the horn.

On the steering column will be a red thing with loads of wires connected to it. It's a starter safety interlock unit. It's as much use as a Bollock on a teapot and can be discarded.

Connect the Grey wire which was on the starter safety interlock unit to the Horn. You can now amuse seven year old kids by doing Dalek farts with it.

[phattanglo]

So Del I've googled the old school regulator and it keeps coming up with 3 pin ac only regulators.
Can you advise which is the correct one to look out for and which coloured wire goes where.

With regard to the 2 yellow wires to the horn, will the one not going to the horn switch become redundant when the grey wire from the starter interlock is used.
I'm trying to get the wiring as basic as possible and while people might think I'm crazy, as soon as I retire and I don't need my scoot for work I'm seriously considering a drum front end to replace the standard disc setup purely for aesthetic reasons.
I don't think crap brakes will be an issue as by the time I'm retired the Nanny state will have set a 20 mph speed limit for everywhere.

[del]

 This is rubbish. I have amended this below under urgent update. Please ignore me.

Hello. It's definitely a 4 pin one.
I live in the UK. There's an earth terminal. two yellow terminals at the end which the black and blue wires from the stator plate connect to. the red terminal connects to the red/white wire. the rest of the wiring can be tucked out the way.
The yellow horn wire is in the DC part of the circuit and will be dead without a battery. The grey wire is 12V AC. I'll post a part number for the regulator when I can find it.

[phattanglo]

Cheers Del I've found a 4 pin regulator on the SIP website which is for a Cosa, the rest are either 3 or 5 pin.
To be honest I probably could also revert to a 3 pin as I've dispensed with both the starter and the battery or does it depend on the number of wire coming out of the stator?
Am I right in thinking that I could also incorporate the horn wire with the ac wire at the regulator end that goes to the indicator unit and leave both the yellow wires on the new ac horn.

[del]

Yes you can wire the horn up that way. I just did it the way I described as the Grey wire in the horn cover was already there doing nothing. What I wanted to avoid is the DC wiring goes through the ignition switch and think that's another weak link. I did everything so it is reversible apart from the Starter motor since I knocked the ring off the flywheel anyway. But if in future I want to have a battery I can reverse what I have done easily.

I suppose there's no reason not to use a 3 pin regulator. The wiring would be slightly different that's all. The Stator only has two wires Black is earth and Blue is unregulated AC. the ignition wires are separate and go directly to the CDI.

[phattanglo]

Just one more thing Del, mine is a 2012 model so it has the new style stator with 12 coils on it and just 4 wires.
Is that the same as yours or will I have to investigate a bit further?

[del]

URGENT UPDATE: SORRY I DROPPED A BOLLOCK.
The regulator is in fact a 3 pin one. The wires left to right are G = Green and grey. G = Blue earth = Black wires.

I have amended the posts above. Hello Phatanglo. Mine is a 2012 model too 12 Coils and all. That’s why I always look at your posts. Most times I know what I’m on about.

[phattanglo]

Cheers Del,
That's a big help.