Lucas Altette Car horns on A10s

[KiwiGF]

Ha! Just done exactly this except I rewound the coil so that it was 6v rather than 12v. Very simple in that you unwind the coil fold in half and solder the conection onto the middle and then the two remaining ends together, so twice the thickness but half the length. I did this with an aluminium bezel version for my bitsa RE Bullet with great succes some years back. With a Super Rocket one I got the wavy centred horn with the steel bezel. Made new dome headed ba screws for the rim and have them and the bezel off at the platers now.

Out of interest is this method of rewinding only easy on the horns with a core gap adjustment on the rear? The coil on those horns without adjustment appear to held in place by a pressed on washer that looks tricky to remove.

[Slymo]

I think the days of cheap Altettes from the wreckers are long gone. I ravaged my older bro’s supply for mine.

[trevinoz]

A six volt coil has sixty turns of 0.8mm wire, I have made many of them over the years. This is for the type C but works equally well for the others.
The type B had 68 turns of a lighter gauge.
The armature movement should be in the order of , I think, 0.011" to 0.013".
It varies with the condition of the diaphragm, some work very well with 0.010"
Some trivia, the type B which was introduced for 1949 had a round body for that year only but had the flats the next year.

[trevinoz]

Further to this on re-reading the first post.
The cast iron body was first used in 1949.
From 1937 - 48 the body was cast iron with 3 screws on the back, 2 for the points mount & 1 for points adjustment.
They were all HF 1234/1235 regardless of the body type.
I don't think that the alloy bezel was used on motorcycle horns though plenty are there now, I have never seen an original 6v horn so fitted, only 12V.
The wire gauge on the early horns winding was 0.6mm, 68 turns.
To rewind, the points have to be removed, easy on the pressed steel body but rivets have to be drilled out on the others.
To get at the winding the retainer must be butchered out, brass on early, aluminium on late.
The horns up to about 1946 had the winding encapsulated so must be chopped out.
I fit the new winding and seal it in position with RTV compound, usually non acidic.
I think that the horn with the rear pole adjuster was first used in 1952.
These are the easiest to get working, no need for multiple gaskets under the diaphragm.

[Butch (cb)]

I picked up a good looking and original Altette from ebay a couple of years back. All still with nicely chromed furniture. I must have lucked in as it really wasn't much money.

It turned up with connecting wires still attached but clipped an inch and a half or so away from the connectors. Left me with the horrible feeling that maybe the vendor had just half inched it from someone else's machine. It's quite out me off ever fitting it.

I have a certain paranoia for leaving my bike in the same place twice for fear someone would steal the clock - mine is on the cafe racers style plate mounted on the top fork nut. I guess after the speedo the horn is then best highest value and easiest thing to remove.

[KiwiGF]

I picked up a good looking and original Altette from ebay a couple of years back. All still with nicely chromed furniture. I must have lucked in as it really wasn't much money.

It turned up with connecting wires still attached but clipped an inch and a half or so away from the connectors. Left me with the horrible feeling that maybe the vendor had just half inched it from someone else's machine. It's quite out me off ever fitting it.

I have a certain paranoia for leaving my bike in the same place twice for fear someone would steal the clock - mine is on the cafe racers style plate mounted on the top fork nut. I guess after the speedo the horn is then best highest value and easiest thing to remove.

I hope yr bike is not tampered with but I hope you can see from this thread your best insurance is to pick up a suitable car horn “just in case”!

Whilst I can understand those involved in supplying horns for our bikes need to earn a living, and restoring them is not the quickest or simplest job (so I have no problem with prices like 200gbp) but just for those who want to get an adequate horn for next to nothing I hope this thread has been useful.

I bought 6 horns “randomly” for a total of something like 20gbp and I’ve got 2 half decent ones from those with no additional cost apart from a bit of paint. Some mates will no doubt get the spare ones off me as I’m easily bribed with a beer  .

I have not taken the option but on top of the purchase cost would be the cost of a chromed bezel and set of nuts is what you want to get the correct look, and there are a few sources of these (some cheaper than others). Hopefully this thread will enable readers to pick up the correct horn from a car breakers etc. if you are a rivet counter (no offence) you should be able to make sure you have the correct number of nuts on 5he back of your horn 

Cudos to Trevinoz who has provided some “missing bits” of information, and also given us the method and coil specs so we can make a 6v horn from 12v, that’s my next mini project. I’ll report back how that goes with some pics (unless Trev beats me to it).

[Bsareg]

I was at the VMCC festival of 1000 bikes at Brands Hatch when a call went out over the Tannoy to keep our eyes out for someone carrying a Lyta tank pinched from one of the bikes there. Never heard if he was caught but there are a few good high trees at Brands if he was.

[chaterlea25]

Hi All,
I'm sure I heard of a similar story a while ago
Hanging is too good for the bsatards

I remember some years ago seeing "security" tank centre bolts advertised
Wish I had bought some then
At the moment I have two tanks being repainted one is an original RGS that has been de dented and rechromed
the other is a copy but quite a good one, I need to come up with something like those bolts above 

Friends with vintage cars always remove radiator and other easily removable item when they put their cars on show
About two/three years ago at Stafford the stall holder next to me had a chronometric speedo stolen
later that day I spoke with another stall holder who had a rare magneto stolen
I keep all the goodies in perspex covered display boxes now, and have resorted to tying a few big items to the table using inner cable

John

[trevinoz]

Kiwi, a couple of pictures of the new coil and as fitted.

[a101960]

I remember some years ago seeing "security" tank centre bolts advertised
Wish I had bought some then

John, as far as I am aware, these bolts are still sold by George Prew.

[chaterlea25]

Hi A10,
Thanks, I will check with him
John

[Slymo]

Got the rim and the new 3/8” homemade dome screws back from the platers today. Gotta say I’m chuffed with the result. Certainly prettier that the house paint yellow one that I got from my Bro.

[kiwipom]

hi Slymo,  nice job will it fool the `bean counters` cheers

[Slymo]

Hope so, my mate suggested punching Altette into the rim prior to plating but I thought that was asking for tuts from the anorak brigade. :)

[Black Sheep]

Punching Altette onto the rim. Hanging offence clearly. It's not just tanks that can disappear. Came back to my Norton once and found it minus timing cover, rev counter gearbox and rev counter.  So it must have been a fellow Norton owner. Rather disappointing. At least he left me the screws.