The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Steverat on 18.12. 2018 00:04
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Josef's bike has a Lucas Altette which needs both cosmetic and functional refurbishment. It has a short circuit internally somewhere and makes no sound when 6V are applied though there are sparks at the terminals. Do you know a place who might be interested in doing this?
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Some just need adjusting... put power to it, Undo that lock nut on rear and adjust with Cheese head slot with screw driver... Sometimes the contact in there has gotten dirty and stops the vibration (which makes the noise).
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Taff the Horn is the man
http://text.taffthehorns.com
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Josef's bike has a Lucas Altette which needs both cosmetic and functional refurbishment. It has a short circuit internally somewhere and makes no sound when 6V are applied though there are sparks at the terminals. Do you know a place who might be interested in doing this?
Not an answer to your question but lots of info here https://www.a7a10.net/forum/index.php?topic=13278.0
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Taff the Horn is the man
http://text.taffthehorns.com
Taff the Horn is brilliant, done a few for me in years gone by, he can talk the hind leg off a donkey though!!
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taffthehorns' website seems like it's having trouble. No images coming through for me.
Richard L.
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He may advertise in Old Bike mart and puts adds in their wanted section as well, he can chat.
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If you ar stuck, they are rugged and simple things so you should be able to repair it. Give it a good clean up and try adjusting the make and break contacts as previously suggested. The paper gaskets may have disintigrated but you can easily make some more. They need a good battery to work as they draw a lot of current.
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Thanks for the replies, I see Taff gets a lot of praise.
But there are brand new Lucas horns available too:
https://www.classicbikeshop.co.uk/6-volt-lucas-altette-replica-horn.html
Any experience with these?
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Thanks for the replies, I see Taff gets a lot of praise.
But there are brand new Lucas horns available too:
https://www.classicbikeshop.co.uk/6-volt-lucas-altette-replica-horn.html
Any experience with these?
Got one on the plunger. They are ok. Paid € 120 for it.
Really good quality, sounds good but still are repro so if you want it to be original it may be more interesting to have the original restored. Up to you.
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Hi , i have a genuine Lucas Altette for you in working condition, the chrome is very good but the black paint in the back needs doing.
E120 + postage .i can email you pictures if you want.
cheers.
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Don't touch that lock nut or adjust the centre screw.
This should be set initially to give the desired armature movement.
The adjustment is done firstly under the dome nut on the front and fine tuned with the small screw on the rear.
This is for this particular model.
However, this is all academic if someone has been there before you and had a play.
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Don't touch that lock nut or adjust the centre screw.
This should be set initially to give the desired armature movement.
The adjustment is done firstly under the dome nut on the front and fine tuned with the small screw on the rear.
This is for this particular model.
However, this is all academic if someone has been there before you and had a play.
Oh heck I played with it on the bench tonight and the first thing I went for was the lock nut and screw. Got it to work too, sounds like an angry bullock. Yes, bullock. Not two of them. Flushed with success I then tried to strip the unit and came to a full stop when trying to unscrew the nut on the front underneath the big dome nut. It won't shift, and I'm a bit wary of forcing it since it sits in the middle of a delicate-looking diaphragm. Now that I have already sinned, I want to go all the way. I'm leaving the central front nut dripping with plusgas overnight in the hope it will yield to my desires in the morning. Which model have I got? Can you tell?
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It is an HF1234 from about 1952 on.
You don't need to remove the diaphragm nut to get into the innards, better if you don't, it saves you having to get it into the right position on reassembly.
You will need to loosen the pushrod in the centre of the armature, you really need a special tool to loosen the lock ring first.
The armature assembly will slide from under the points arm and can be lifted out.
Give the points a good clean and check for continuity with a meter, they can be difficult to get really clean with a good low resistance.
Fit new gaskets either side of the diaphragm and reassemble. The gasket thickness is not critical on this type, unlike the earlier ones.
The next step is to set the armature travel. It needs to be about 0.010" with a good loud click as it hits the pole which is adjusted from the rear via the threaded section and locknut. The pushrod has to be backed off or not in place while doing this.
After the travel is set, adjust the pushrod to get the best sound. Fit the dome nut and fine tune with the rear points adjusting screw.
Simple.
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Don't touch that lock nut or adjust the centre screw.
This should be set initially to give the desired armature movement.
The adjustment is done firstly under the dome nut on the front and fine tuned with the small screw on the rear.
This is for this particular model.
However, this is all academic if someone has been there before you and had a play.
Oh heck I played with it on the bench tonight and the first thing I went for was the lock nut and screw. Got it to work too, sounds like an angry bullock. Yes, bullock. Not two of them. Flushed with success I then tried to strip the unit and came to a full stop when trying to unscrew the nut on the front underneath the big dome nut. It won't shift, and I'm a bit wary of forcing it since it sits in the middle of a delicate-looking diaphragm. Now that I have already sinned, I want to go all the way. I'm leaving the central front nut dripping with plusgas overnight in the hope it will yield to my desires in the morning. Which model have I got? Can you tell?
Further to what Trev said, once the nuts around the edge holding the bezel and diaphragm the diaphragm will come out, but has to be slid over in one particular direction first. It helps to know which direction of course, from memory you slide it in the direction AWAY from the terminals. If you look at some pics of ehe internal you will see why, the piece held on by that centre nut “interlocks” with the contact breaker.
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Don't touch that lock nut or adjust the centre screw.
This should be set initially to give the desired armature movement.
The adjustment is done firstly under the dome nut on the front and fine tuned with the small screw on the rear.
This is for this particular model.
However, this is all academic if someone has been there before you and had a play.
Oh heck I played with it on the bench tonight and the first thing I went for was the lock nut and screw. Got it to work too, sounds like an angry bullock. Yes, bullock. Not two of them. Flushed with success I then tried to strip the unit and came to a full stop when trying to unscrew the nut on the front underneath the big dome nut. It won't shift, and I'm a bit wary of forcing it since it sits in the middle of a delicate-looking diaphragm. Now that I have already sinned, I want to go all the way. I'm leaving the central front nut dripping with plusgas overnight in the hope it will yield to my desires in the morning. Which model have I got? Can you tell?
Further to what Trev said, once the nuts around the edge holding the bezel and diaphragm the diaphragm will come out, but has to be slid over in one particular direction first. It helps to know which direction of course, from memory you slide it in the direction AWAY from the terminals. If you look at some pics of ehe internal you will see why, the piece held on by that centre nut “interlocks” with the contact breaker.
Many thanks to you and Trev for the guidance, as you can see I’m up early to try it out in the garage. But 4:30am start is furtive even by my standards - SWMBO will be on warpath if I am found there before breakfast. There will be an interlude for Xmas and I shall post again in January. Once again many thanks for your help. Have a great Christmas! I’m sure you will do better than us on the weather front for starters.
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Oh heck I played with it on the bench tonight and the first thing I went for was the lock nut and screw. Got it to work too, sounds like an angry bullock. Yes, bullock. Not two of them.
That's close, just some fine tuning is needed.
I was told to adjust until it " sounds like a sick cow in heat"
*eek*
Glen
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Thanks Kiwi and Trev,
I managed to strip it as you advised, now I bought some new dome nuts and I'm having the existing bezel rechromed, so with a lick of paint it should look good again. However (like Della Street)_ one thing puzzles me - the threads in the holdng bracket locations are 1/4" BSF, but the other 4 are about 3/16" - of course I can tap the smaller ones out and use 1/4" studding for all of them but I just wonder what the smaller ones should be - a 3/16" tap will go through them with lots of clearance but the 1/4" tap will not go in.
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Hi Steverat,
I think the threads are 1BA *????*
Just to add more confusion *eek*
Open to correction?
John
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When I did my 1936 horn a while back I'm pretty sure they were indeed 1BA. In my experience only manufacturers of electricals ever used odd BA sizes, although there's bound to be other applications.
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They are definitely 1 BA.
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Yes you are right, it’s 0BA on the mounting stud holes and 1BA on the other 4. So it’s either make up 2 stepped studs or have different nut sizes
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Yes you are right, it’s 0BA on the mounting stud holes and 1BA on the other 4. So it’s either make up 2 stepped studs or have different nut sizes
I’m fairly certain you can buy dome nuts with the same across flats size, but having different thread diameter to suit the two stud sizes. See:
https://www.ebay.com/itm/LUCAS-ALTETTE-HEX-domes-USE-with-FLAT-ALLOY-Disc-Lucas-Nuts/362515649325?hash=item54679dd32d:g:a-EAAOxyOalTZ8N~
Also I vaguely remember when cleaning out the threads one of the two ba sizes is same as bsf, or close enough.
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The large ones are not 0 BA but are definitely 1/4" BSF.
0 BA has a pitch of 1.0 mm and a diameter of 6 mm which is close enough to allow a screw to mate up to 1/4" BSF.
All of the acorn nuts are 3/8" AF as are the two 1/4 BSF nuts which secure the horn to the bracket.
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Thanks, I think I'm close to having it sorted now. got the 2off 1/4" BSF and 4off 1BA nuts and the studding is coming to suit.
One more thing - the terminal screws. Mine are missing. If they are BA the sockets look like they must be 3BA??????
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That would be 2BA, Steve.
Special hex head slotted screws. 1/4" AF brass.
Your picture shows one of them in place.
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*red*
Dont know what happened to it, not there now...
Thanks Trev.
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You can probably get them from Taff or use a cheese head screw.
While you have it apart, lubricate the adjusting screw in the points, I use Neverseez or similar.