Does anyone have any technical details for overhauling a Lucas Altette horn? There are a couple of screws with lock nuts to set gaps, but I've no idea what these gaps should be. Parts inside the horn body are riveted in; do these need removing as part of the overhaul? An exploded view or drawings would help.
These Lucas manuals might help.
That's just what I wanted, you're a star.
Very typical Lucas horn adjustment details. Very detailed but can be by passed to a basic instruction- I was going to add before the manual came up that the actual gap can't be set as such as it is closed at rest, the gap only appears as the unit jumps into life. At which point one usually adjust for maximum 'noise', but you should be doing this off a decent battery supply, it won't happen on the average old fashioned battery charger. The other item I find useful is a large T shirt to stuff up the orrifice (rubbish speffling-no spef checker). Don't annoy the neighbours too much.
Thanks for the practickle advice!
I have a similar prob, Phil. Any tips from the work you've done.
Like how to lock that silly little lock pin for the push rod?
Or anything else you've come across?
By coincidence, just 2 weeks ago I dismantled and refurbished my very dead ES2 horn. I needed to uprate it to operate at 12 volts and not kill the battery each time the noise button was pushed.
It is not the easiest of bike chunks to dismantle and I only worked out the proper procedure after adding more damage to the already very corroded and broken internals.
There are people who can rebuild these horns......at a hefty price......so I took the easy option instead of buying a cheap scooter/moped horn. Then, wanting to challenge myself I removed most of the original internals to provide space for the new horn to fit inside. Of course, on reflection I could have just mounted them back to back but that is too easy. My efforts have been rewarded with a very loud horn that now operates on demand.
Attachments show start and nearly finished points.
Google Taff the Horn.
Very useful guy and website.
I bought a new coil for mine. When dismantling the horn remove all of the studs. The diaphragm can be removed without removing the push rod assembly. The studs are BA size.
The gaskets each side of the diaphragm also act as shims so affect the adjustment. I had a couple of gaskets each side. I broke one and left it out. I could not adjust the horn at all. I made a replacement and it all worked again.