my '61 BSA super rocket is negative earth... really?

[bsa-bill]

I'll have to read that a time or two before it sticks groily but a great post

as old Joe had to invent something to do all that it's no wonder he advised us not to venture out after dark 

[duTch]

 Ok TT, thanks....um B-Bill       

Strange old day today
I just read a Dutch fella from New Zealand and a Scot d

 Who's the Dutch guy frum UnZeelund.....???   .... maybe Mikeb..??.....my Granpa was a real Scott Scot (but not the GREAT Scott)who went there...

      TBC

[bsa-bill]

Oh No !! I'm seeing more stars than I should now as well as big red buses.
Apologies to however many nations I've managed to insult
I do need to hang in to this thread though, I've just got the battery and wiring to sort on the Flash now and it's done, I've had trouble sorting this harness out previously and got to  do it again, beats me how such a simple wiring diagram can lead to a harness with so many surplus, additional and wrongly coloured wires, and the little paper labels I put on the last time have faded so I can't read them, no remarks re Specsavers please

[RichardL]

B-Bill,

Not saying that I would automatically know any better how the harness goes in, but I'd enjoy helping to suss it out over, say, three beers. You just happen to be a bit far away to hop on over.

Richard L.

[bsa-bill]

Appreciate the thought Richard, think the three beers sounds good.

[duTch]

 Well  (x3x2- each one comes as a pair ) all 'round I say, and especially for Groily for that epic story.... now that I had a chance to read it...a bit easier to take in than the explanation in the Lucas book. ...Richard your point was kinda what I was too lazy/didn't have time to make- well mainly just regarding the polarity of thefield magnet thanks
  Could be wrong, but I think I figured there's a couple of different configurations of connecting the brush wires to the 'F ' / 'D ' To produce the same result and same for opposite (think direction of motoring)....?
 Groily- ¿is 'remanent' the same as 'remnant'..?
 B-Bill, there's one of those buses truckin' 'round my area lately too. ...

[groily]

Ha! Well same origin probably, but remanent just means residual in this case Dutch, a hangover from the last time it ran.

You're not wrong in raising the dynamo wiring configuration, but a standard Lucas will have one end of the field coil to earth, t'other to F terminal, one brush to earth and t'other brush to D. Which end of the field is to earth, which to F (and which brush to D and E), determines direction of rotation; swapping one or the other reverses it. Swapping field leads AND brushes would bring you back to where you started.

Miller dynamos and most 'continental' ones aren't the same (and also have an additional resistor winding that can be confused with the field coil), and some Lucas will have been modified to 'Miller' spec to accept some types of electronic regulators, JG in particular, which regulate on the opposite side. (Because you can regulate on the earth or the live side of things.)

But if a dynamo is wired as standard, no problem. You then just choose your direction of rotation and polarity, both of which I always confirm for myself by motoring them with a battery (for positive earth, batt negative to F and D joined together, positive battery terminal to dynamo body). And then away she should go, if she's going to that is! Cheers.

[mikeb]

groily that was a helpful post and dutch thanks for defending the honour of our respective nations. side question - how do you get those little flags in your post's footers?

ok so but back to the first question: as the plot thickens maybe you can tell me this -
- if the regulator is really an easier place to disconnect the dynamo wires then I'm assuming i have to pry open the case - its an RB108 and from what I've read the wires are soldered in.... true?
- or can i just get the cover off the back of the dynamo and disconnect and test it there?

I'm hoping this is just a case of an unused bike's dynamo needing reflashing. new battery arrives tomorrow.

cheers

Mike
Mod edit: Like that one down there!

[groily]

I'd have thought it would be easier to disconnect D and F at the dynamo. Have you got external plugs on a bakelite end cover and steel strap, or is there a one-piece metal cover with the wires plugged in on the inside? In the former case, undo the little screw on the kidney-shaped bit on the outsdie (if it's still there the way Lucas intended) and pull out the 2 wires; in the latter, just undo the central cover screw, remove the cover being careful with the wires and the grommet, and all will be revealed. Then you can do your tests.
Can't recall whether on RB108s things are soldered or plugged in (can't even remember the Lucas numbers for the different versions!) - as I haven't messed with a mechanical regulator for years, preferring ManorMike's DVR2, as do quite a lot of us. It's as likely the regulator is the cause of any problems as it is that the dynamo is misbehaving to be honest - but for setting up the regulator properly if that's the problem area, you need to wait until Trevinoz or some other resident mechanical regulator expert comes along! Cheers.

[mikeb]

thanks groily. i'll have a look at that tomorrow and see how far i get

[bsa-bill]

Have you got external plugs on a bakelite end cover and steel strap, or is there a one-piece metal cover with the wires plugged in on the inside?

Daft question coming

I don't suppose for 1 minute these are exchangeable, really don't like that strap affair, it's the type on my RGF so it doesn't really matter for originality just have had some issues with corrosion on the wires and so forth

[duTch]

 Not so daft B-Bill, I have the latter one piece jobbie, but I have a feeling there is a minor difference to do with an 'O' ring and also a locating kind of lump/notch...I have one of each will have a looksee.....only thing is, with my recent dilemma, I did note that the bakelite/strap cover has a bit more room for wires to not engage with the cover and rub/wear/short-circuit/blowup.....and if the joint is at the bottom for drainage, is at least a step up...and I shall now recommend some rubber inside for wire protection

 Thanks Mikeb, but I was more making sure B-Bill wasn't calling me a Kiwi- no offense, but I went into a cold sweat when my Ma informed me at age about 30, that I was almost born such.....    she was a born Aussie but when they left UnZud to go to Scootlun, they left her Bro there (turned out, he later became my uncle) maybe they didn't like him or he missed the boat-dunno.....but when she married my Dad, wanted him to go live there- nuhuh noway getfar***f***off.....he was stayin' home after being in all the wartorn places.....
 

 And TT...for the record, what you suggested about wires changing polarity is usually the kinda crap thing I'd say.....!!

[Triton Thrasher]

And TT...for the record, what you suggested about wires changing polarity is usually the kinda crap thing I'd say.....!!

This?

Wires don't change for change of polarity.

I find it to be true. Changing a dynamo's polarity doesn't involve changes to wiring.

[u28909z]

It is possible to swap the strap type end cover for the one piece metal one. Just need to file down a small locating boss from the end housing, and replace or modify the brush plate, as the wires should now plug into this internally. The later brush plates are available but cost £20-30 to buy new.

I have modified one myself, altering the old brush plate was the tricky bit.

There are pictures of the brush plates on some of the dynamo specialists sites.

Arthur 

[bsa-bill]

Thanks for that Arthur

got it copied to my "bike bits and bobs" document