[Clawed]

If anyone is still interested in this question, Harley have used a twin lead coil from about the late 20’s.
I have used WLA coils on various things over the last 10 years or so, 6volt, easy to get and the current quality and price seems ok.

Clawed

[Clawed]

It does not look like a 2 brush Lucas dynamo. I do not say I know all of them but it is not like any Lucas one I have seen. That means D and F may not be valid.
Bosch use D and F but their regulator is the earth side of the field coil and Lucas is on the power side. The internal wiring in the dynamo can normally be changed to suit either regulator.
Miller have something similar to Lucas but the cut out is inside the dynamo and the connections are D and S. I have no practical experiance with Miller but the dynamo internal wiring can be changed to suit the Lucas regulator. Apparently this is an improvement.
If it is a BTH it will work excellently by some obscure theory that no one understands any more but a few will know how to make it work.
The few PAL and CAV dynamos I have seen are similar to the Bosch. To motor them the F is connected to earth and D to power.
I would suggest you take the dynamo to some one who knows about old dynamos as they can all have their internal wiring changed to suit the various regulators.

Geoff

[Clawed]

One of the terminals should have about 3 ohms resistance between its self and the generator body. This will be the F.
The other should have not much between it and the generator body and it may vary a bit as the armature is rotated because there is two brushes between it and completing the circuit to earth. The F terminal resistance should not vary as it does not go through brushes.
This assumes it is a Lucas and has not been modified for say a Bosch regulator.
If you can see inside the geni the wire from the D terminal will go to one of the brushes and the F will go to the field coil. The other brush and other end of the field coil should go to earth.
The generators earthed through the body so a really good paint job will mean no earth. Rare that paint insulates that well with all the bolts and clamps and stuff but worth checking back to battery earth.

Geoff

[Clawed]

Hello Mr. 59 / 57 Birmingham,

If worst comes to worst and you can not move the pistons, drill the top of the pistons and get into them with a die grinder and large course burr and chew away behind the rings, then pretend you are working on a Harley and smash the ring and bits of piston with a cold chisel. If it frees up after that it was the rings that were stuck, if not you will have to split the piston with the burr and probably a sacrificial screwdriver. If you buy or borrow equipment make sure that you can reach far enough down the bore with it. Aluminium is a pain with burr’s, rubbing french chalk on the burr helps a bit, as with files.

I have never had a problem with dumping moderatly heated casting ionto cold water, I have dumped 125 K.T.M. castings and 50’s Matchless singles into cold water on many occasions. The only problem encountered was the a bent conrod on the K.T.M. Twice, in four years. I learnt something from that, avoid crashing in rivers.
I know iron oxide, and most other metal oxides are considered insolubile in water but the only reason water is used is it is a low viscosity fluid. Anything of similar or lower viscosity will do. But water is cheap and non flammable etc. I know Keith spent a day dissassembling a late teens or early 20’s Velo when the previous owner had tried for 20 years to dissassemble it. To the previous owners credit he had not destroyed anything.

Geoff

[Clawed]

Hello all,
I was taught a technique for dissassembling stuff that was “oxided together” by a fellow named Keith Hamilton, well respected amongst Velocette owners in Oztralia. Sadly passed away a few years ago.
It is basically heating the component to about 130 degrees Celcius and dumping it in cold water until it is cold and seeing if it moves. If it moves leave it in the water and work it until it frees up, which will not be long. If it does not move, do it again and repeat until it does. The theory is that dry oxide is full of air, and heating it up and dumping in cold water means the oxide sucks in water. Oxide full of water is mush.
My first experience of this was a 1925 B.S.A 350 frame steering head locknut, the usual domed head thing. It was rusted through to the threads on one side and the hex was only a vague outline. After about 4 heatings and dunkings it started to move and leaving it in the water the oxide washed out and I unscrewed it. The steering head thread is undamaged and as a locknut the nut is still useable, although the only spanner to fit it is the multigrips.
Geoff

[Clawed]

I notice both of us who like the brake are named Geoff.
Obvious solution is to change your name to Geoff. Easier than mucking about with the brake 🙂

Geoff

[Clawed]

Hi, Geoff Ingram from the wide brown land of Australia. It is nearly summer and the bloody heater is on.
I have had a 1949 Scott for about 5 years now and have to say the front brake is about the best drum brake I have ever used. It is easily a match for a good mates Velocette Thruxton twin leading shoe
When I first bought the bike the brake was not very good but a good clean and grease of the box transformed the brake.
I learnt in 1980 as the owner of a 125 KTM enduro bike that drums like to be clean and correctly lubricated to work properly.

The performance of the twin front brake on the Scott has nothing to do with how how the box is mounted to the front muguard.
The forces of the inner cables are taken by the outer cables, the compressive forces from the handlebar lever go through the outer cable from the handlebar lever to the box, through the box to the outer cables from the box to the brake plates. The brake may well work a little better if the box was just floating around as the cables could then be in their “natural” position. Although the rattle and scatched paint could be a pain.
If anone tries this could you let me know the results. Braking results not rattle and scratched paint results.

I have been having a wonderful time with my Scott of late.
Friday I found a cracked left crank.
Saturday I found a cracked right crankcase.
I am hoping Roger Moss has some cranks to sell.
If anyone has advice about welding crankcases I will listen.
At the moment I am considering using an aluminium brazing rod called Ultrabond. Its melting pont is only 380 degress C and strength greater than aluminium.
Strength of bond can be good depending on stuff. Mainly cleanliness.

Geoff

[Clawed]

Pound sign is the Alt key and 0163.
I am from Australia. 8)
Not that I’m rubbing it in or anything. 🙂

Clawed

[Author]

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