[Clawed]

Hello Mike

Could be a crook condensor. If your bike has a magneto that is difficult to change so check that is the real fault.

If a battery coil ignition it is easy to change and all ignition condensors are about the same electrically (not sure I spelt that right) you just need to be able to fit it in your bike. Could be a coil too. If you can feel a warm spot in the coil it is failing, that is not a diffinitive test but an easy one that means imminent failure.

Geoff

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Hello Al

Try Roger Moss’s website, mossengineering.co.uk, he has links to Technicalities and some useful stuff on his website. He also does truly excellent work for what I consider a fair price, but not cheap.

Rogers website has had nothing done to it for quite a few years but it is still there. His son set it up but got busy with his own life and family.

Geoff – The wide brown land of Oz

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Hi Bob

If it is the crank seals being dry you might try disconnecting the feed lines to each cranckcase at the oil pump and squirting some oil down each with an oil can. The opening is timed so maybe turning the engine over slowly may help.

Good luck.

Geoff

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Hello Iain

Don’t forget to turn the oil tap on.

I have no experience of Silk oil pumps, but what I have read does not seem to be what you have.

You seem to have a pump with 2 outlets, 1 for each cylinder, from what I have read Silk pumps split the outlet to both cylinders, that idea could be a bit dodgey? George made a successful motorcycle, so I’m not sure.

I would be quite carefull about dismantling the oil pump, if it seemed to work ok I would leave it alone.

What type of oil to use in a Scott? How many answers do you want. Opinions vary wildly, from cheapest crap you can find, to the latest synthetic. Whatever you get it will probably be as good as whatever was used in the late twenties, when it was designed. I use a 40-70 (Penrite HPR-50)in the oil tank and 50 or so to one of mineral Castrol blue smoke in the fuel, not too particular about the ratio. I have a Pilgrim pump with a 4:1 reduction ratio running 3 spits to a drop.

Mine has the gearbox drain plug as the front lower outer cover bolt, it’s a hex head. Mine’s a 1949 model.

Scott normally took pride in not having to add oil to the fuel, but I have no experience with the Birmingham models.

Geoff

 

[Clawed]

Hello Dave

I think you are correct in the magneto driving the oil pump on the earlier models, mine is a 1949.

There is a ‘publication’ called Technicalities, which was available on the old website, but I could not find it here. There is also Son Of Technicalities, which was also avalible on the old website, but again, I could not find it here.

I remember reading about ‘better’ ways to drive the oil pump. I am quite sure these would have answered your question.

Geoff

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Hello Peter

Make sure you have the correct sized ball in the external indent mechanism, I think it is a 9/32″ ball, but it may be 7/32″. It is not 1/4″. Graham at the spares has them. Mine had the wrong size ball when I bought it and the gearchange was “interesting”.

Geoff

[Clawed]

Hello

In my experience with the foot change gearbox if the 9/32″ ball bearing in the indent positioner is replaced with a 1/4″ ball the gearchange is very uncertain. See Scott Technicalities, Transmission, Three speed, A Beginners Guide To The Scott gearbox.

 

Geoff

[Clawed]

Hello Dave
As I remember the head studs go about 5/8″ into the cylinder casting. The hole should be deeper than that. I am fairly sure the thread into the cylinder casting is 5/16″ BSF, 22 TPI. The tapping size is 6.9 mm, or a letter ‘I’ drill size, if running a slot drill through a 17/64″ would be about right.
There are plain steel and stainless steel studs and nuts available from the club spares. I have no idea if the stainless steel will help in the future. I am not a fan of stainless steel used for non decorative purposes.
I see you are in Canada, I am in Australia. I would guess your machine shops are comfortable with imperial or metric units, as many in Australia are, so I have given both.
You may want to think about picking the threads out of the cylinder block yourself. if the machine shop drills them out, the remains of the threads may be a bit stuck in the block, this could be a painfully slow job to get the first few threads out with a pick, so a tap can be started, it may be quite expensive in time. Depends on your level of expetise and patience.
Best of luck

Geoff

[Clawed]

Hello Dave

Sorry I didn,t reply to your post of 17 August, I was a bit distracted by other things.

Very glad to hear the barrels freed up and nothing damaged.

Do not ever pry the head off!

Removing seized head studs can be a fun job. If you have access to, or someone willing, it can be quickest to machine them away on a milling machine. Saw them off above the head and machine them away inside the head with a slot drill or centre cutting end mill. Do not forget drilling into the studs at barrel height needs to go down to, at most the tapping size for 5/16″ BSF, (I think the barrel threads are BSF and the nuts 5/16″ CEI).

Another way is to heat the whole assembly to about 100° C and dump it into cold water until it cools down, then using something like a wooden hammer handle, hit the inside of the head a few times and see if it moves. If it moves keep it in the water hitting the head up and down until it is free. If it doesn’t move, repeat the heating as many times as nesscesary. I do realize a head and barrel assembly is a big lump to heat up. This can be a long and slow process but you end up with everything useable again.

This was told to me by an Australian Velocette guru, Keith Hamilton. The idea being corrosion has a lot of space for air, if you heat it up and dump it in water it sucks the water in to the corrosion. The corrosion will turn to mush in the water. Once it starts to move the water will move in as you move the parts.

People will say you can’t dump a hot cast iron into water, it is at about 100° C, I have ridden plenty of cast iron cylinders through creeks, as had Keith, and every old trials rider.

Geoff

 

[Clawed]

Hello David

The drawing in Technicalities uses the gears from a 3 speed Sturmey Archer rear wheel push bike hub. From memory they were the ‘AW’ hub. As far as I know they are still in production, or maybe in production again, not sure. This gave a 3 to 1 reduction drive. I have made one of these, the only critical dimension is the spacing of the gears. Mine is a 4 to 1 as I had most of old Shimano hub left over from push bike days. Apparently Sturmey Archer had these as well.

Don’t worry about lubricating it as I have found the oil in the reduction box is the same colour as the whatever is going through the engine.

Geoff

[Clawed]

Hello Dave

It is probable that the rings have rusted to the bore. I would pour kerosene or WD 40 and leave it for a ‘bit’, (depends how patient you are), put it in gear and rock it backwards and forwards until it frees up. Or maybe frees up. That assumes you can seal the exhaust ports if they are open.

If it is rings rusted to the bore you will need to free them before you can get the barrels off anyway. I would not suggest to take the head of to ‘have a look’ as it is quite likely the head studs have corroded to the head and be much more difficult to remove in the bike than the barrel/head combined.

If it does free up it is up to you to decide whether the corrosion damage to the rings and bores is significant or not. What will you do with it? Classic racing, Cannonball Run, gentle pottering with the local vintage club. If the latter I would just use it if it freed up, see how it goes.

Geoff

 

 

[Clawed]

Hi Dave

If your bars are supposed to be 7/8″ it may have some 22 mm ones fitted. This sometimes causes things to be not tight, and the strip of beer can trick often works well. The strips under a twistgip need to well placed to not interfere with the twist bit.

I know Moto Guzzi and BMW have used 22 mm bars from the 1970’s at least, and I would guess at least some of the other European manufacturers did as well. The Japanese, surprisingly, used 7/8″ well into the 1990’s and may still do.

If your bike has 14 mm plugs, I have had good success with NGK B6EV. I would think any equivalent in that heat range would be ok. I have a 1949 600 Flying Squirrel. Brisk spark plugs from Czechoslovakia seem to be getting good reviews lately from people with oil burning bikes.

Geoff

 

[Clawed]

Hello Geoff

I have reclaimed a set of Matchless G3L steering head races (1951) with a new set of balls and some fine valve grinding paste. I could not find any good ones at the time. This is about 20 years ago. I’m not sure what grade the grinding paste is. It is in a tube with course one end and fine the other. The fine is hopeless for removing pits in valves.

I just lightly squashed the assembly between the chuck and tailstock in my lathe, a drill press would work equally as well. I could hear it ‘growling’ when it started and the growl gradually went away. I would guess I used 300 RPM, lowest speed without engaging back gear on my lathe. I have done another set not long after then, probably for a 1954 MSS Velo. I can’t think of anything else that would have needed it. The Matchless has done about 100,000 miles since then and the Velo about 40,000 miles.

Geoff

[Clawed]

Hello Rick

The stand on the right is off an AJS or Matchless, swingarm single downtube frame,  1950’s.

 

Geoff

[Clawed]

Hello Rob

I have just looked up last time I had the head of my Scott, 1949 DPY motor. I ended up tightening the head to 17 ft/lbs. I initially used 14 ft/lbs, so there must have been a reason why I went to 17, unfortunately I have not recorded why and don’t clearly remember, vaguely remember  a suspicion of leaking to the cooling water. The head was flat as I had just refaced it. It did need retightening to 17 a few times. Mine has original studs which I expect are not mild steel, probably something more like K1045. Good luck.

 

Geoff

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