Replace Stator?

[KerryAJS]

Hello All
Today's question is about my stator, as per attached. I would like to upgrade to 12 volts but read somewhere that if the stator was a 3 wire, single phase, non encapsulated, throw it away.. I think mine is one of these?

Also, I would like a new headlamp, the reflector is not good in mine. However, it looks like the only available headlight with the Lucas Lion on the glass lenses is for a pre-focus bulb and not a H4.. please tell me I'm wrong

[Groily]

Hello All
Today's question is about my stator, as per attached. I would like to upgrade to 12 volts but read somewhere that if the stator was a 3 wire, single phase, non encapsulated, throw it away.. I think mine is one of these?

Also, I would like a new headlamp, the reflector is not good in mine. However, it looks like the only available headlight with the Lucas Lion on the glass lenses is for a pre-focus bulb and not a H4.. please tell me I'm wrong

'Throw it away' may be a bit strong, especially as that one (it is 'one of those') doesn't look bad . . . but the general preference is for the encapsulated sort, two wire stator, given that they aren't (by the standards of almost everything these days) stupidly expensive. But pairing up the 'not common' wires and making sure all the exposed bits are nice and tidy, it'll work I reckon.
You'll presumably be going for something like an A Reg 1 combined 12v regulator rectifier? Good Things, I reckon.

The only other 'maybe' . . . if it's for a '63 350 with coil ignition . . . is that 12v and low rpm don't always go hand in hand,if you're wanting to fit a more powerful headlamp. Been there and done that with an alternator and coil single of another marque, albeit maybe a little bit more plodding than yours. Around town it needed revs to get the charge rate to balance if using more than a 35W headlamp. It'd probably be great with one of the allegedly superior new generation of LEDs though.

People think 'Great, alternator, loads of oomph available' . . . and it's true except that the oomph is rev-related and it takes a few to maintain a system voltage of around 14v with loads on.

'Fraid I don't know about the BP-F vs H4 and Lucas Lion thing.

[KerryAJS]

Appreciate your response and information Groily

[KerryAJS]

Hello All
I have decided to go for a new stator, 12 volts, but there are two types available, a RM21 (120 watts) and a RM23 (200 watts)
I would like better lights, so maybe the 200 watts one?

[Groily]

This is what Paul Goff says on his site, whence many of us buy these bits . . .

"Single phase 12V 120W 2 wire (RM21) LU47205 Pt.no. ALT10109 £89.95 Used with the A Reg Six, 6V regulator/rectifier, this stator is also suitable for a 6V system, replacing the old 3 wire stator.

Single phase 12V 200W 2 wire (RM23) Pt.no. ALT10190 £89.95 These are rated at 200W but max. output is almost 300W at 10,000 RPM.

Use the RM21 if your bike is all LEDs"

Following which good advice, and given the prices are the same, I'd go RM23 if intending to use a 60/55W halogen, or RM21 if going LED as he recommends or if using a more modest headlamp bulb, eg 35/35W or so.

For really good low speed performance around town the three-phase job, at another twenty quid odd, is a good thing but needs the three phase regulator, which is more ££ if you already have a good single phase one lined up.

In all cases I'd use a welded rotor if you don't have one of them on there already. 'They' say - though it's never happened to me - that the early type can self-destruct in certain cases, which could be messy!

[KerryAJS]

Thanks Groily for the information. Just looking at his site, there's an amount of info on there! Do you know if the capacitor can be used with the RM23? Also, I wonder if the LED headlight bulbs are too modern looking with the bulb temperature and if there a major difference between the LED and 60/55W Halogen.. my eyesight needs light at night!
How do you tell if the rotor is of the welded variety?

[Groily]

PG says that only the RM21 is good for a 12v bike with lights but no battery, and a capacitor.
I don't know quite why that is, unless it's a Q of the capacitor, for which he also provides the spec (for original springy thingies, or replacements as sold by him and others) on his site. Nor do I know if the RM23 would be OK if you didn't want lights or a battery, just ignition. Personally, I've only ever used the RM23 on a bike with Boyer Bransden ignition of the older sort (which is power hungry) plus a big headlamp, otherwise I've stuck with the 120W jobs - BUT in all cases bar one, with magnetos.
There is also a pic or pics of replacement welded rotors on PG's site, which you could compare with what you have. Hard to describe exactly the differences as they are pretty similar, but page E13 of the Lucas parts lists for alternators etc shows an old fashioned one, if you can spot the differences from that or any other period literature! See the Archives or, eg http://www.brightsparkmagnetos.com/libr ... 0chart.pdf

Apropos running without a battery, not sure why anyone would unless using the machine for competition stuff while also wanting to retain lighting for riding on the road. A lot of the Competition models used a QD plug to let you get the headlamp unit off quickly, but most standard bikes won't have that. Batteries are probably better 'shock absorbers' than capacitors in terms of keeping things smooth and non-flickery, and I would say - happy to be told I'm quite wrong though! - that starting a coil ignition bike like yours is probably going to be easier with a battery. A capacitor was fitted on my own P11 along with the QD bits, to allow battery-less operation if required, but I put it and much else to one side for the next owner (zener diode, loads of wiring etc) when converting to magneto ignition and fitting an A Reg 1. I think Commandos had the capacitor too, but more as a supposed aid to starting with a flat battery I think. Ie a sort of 12v 'Emergency Ignition' function if you like. I also found I had one on a big Oilfield twin I used to have (but let go to another person who was seduced by its very good looks, as I had been when acquiring it). That certainly did NOT operate as a useful Emergency Ignition source, the thing was a total swine, again with Boyer ignition that required a close to fully-charged battery to get under way.

On the headlamp issue . . . now here's a tin of worms. There are a few threads on here on the topic. I am told that the newest generation of LEDs are fantastic, by some people. My own older LEDs aren't so good apart from as day-running aids frankly, as the main beam hits the moon and the dipped beam illuminates the front tyre. All to do with how they're set up I rather think, in what reflector etc etc - others here have experimented and will have sound advice for you. But they don't use much current, that much is certainly true, and a plus point. Me, I use a bike with a halogen bulb in a concave Cibié unit for dark nights and early mornings, and truly haven't come across anything better so far.

[dave16mct]

I've fitted these to mine: Auxito :
https://www.ebay.co.uk/itm/393614368948 ... 2FWK10GPJZ
Superb headlight, bright and good cut-off for dip.
I also fitted the Auxito tail light bulb and side light bulb.
Dave

[KerryAJS]

Thanks Groily and Dave.
Dave thanks for the "headsup" about the ebay site, but I'm going to stay with the Pre-Focus style of bulb/LED for the moment... but that might be a short moment
Groily, thank you so much for all the information. I was hoping to play with Halogen Pre-Focus Headlight bulb before the LED... I'm a bit old fashioned and like cool temp' bulbs. Also, I want to keep/purchase a headlamp with the old Lucas crest, which the bike originally had? It looks like I can only get a Pre-Focus 7" with that crest?
The reason for the capacitor for me, is not to eliminate the battery but to have a facility to start the bike with a flat battery, like I could with the emergency start facility which will be gone with the two wire stator?
With your mention of electronic ignition, you've set me off thinking about replacing the contact breaker/points now

[Duncan]

Hi Dan, my experience is that I have started both 650 and 350 bikes with batteries disconnected (one was a fractured earth lead and the other I forgot it was off the bike) so you may be worrying unnecessary about installing a capacitor. My basic understanding is that the original emergency start brought all alternator windings into play without regulation, on a two wire system all windings are there all the time, hopefully Bill will confirm if this is so.