Unofficial Royal Enfield Community Forum
Royal Enfield Motorcycles => Vintage Royal Enfield => Topic started by: fxrskrsa on May 29, 2013, 09:16:12 pm
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Hi Folks
My tooter was not tooting very loudly.. So I thought I would get a new one, and saw this one on ebay (see pic) I thinks its a Lucas HF1441 (advert said 1440) and think its 6volts not 12 (as per my bike) I hitched it up to the terminals, and gave it a quick toot, and it sounded fine.. But im now worried that I might destroy this fine old piece of kit. Any thoughts ???
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If I remember correctly they just are louder. Maybe if you hold it on for awhile it might wreck it. ERC
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If it's really a 6 volt horn you could easily overload the wiring on the bike thereby putting Mr Lucas's theory to the ultimate test.
In case you didn't know, Mr Lucas theorized that all electrical current is conducted thru the wiring by smoke.
The smoke was contained by the insulation wrapped around the wiring and if this insulation was damaged the smoke would instantly leak out resulting in a failure of the part (in this case, the horn) to operate. ;D
I'm not sure why a 6 volt horn attached to a 12 volt system will damage the insulation but I suspect it will try to force more smoke thru the insulation than it can possibly carry. The extra smoke will therefore cause a rupture in the existing insulation resulting in massive clouds of smoke escaping.
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So that explains why all Lucas equipment must smoke test itself! :o
The horn is most likely a 6 volt unless altered/rebuilt as 12. They came on many of 1930s/40s models which were 6 volt. Lucas would (should?) have changed the model number if they changed it to 12 volts.
The rounded triangular plate which holds the two wire posts should have a part number, a date of manufacture, and the voltage stated as "6V" or "12V" on it. Maybe under paint or rust or crud, sometimes not stamped very deep.
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They came on many of 1930s/40s models which were 6 volt. Lucas would (should?) have changed the model number if they changed it to 12 volts.
A lot of Brit bikes didn't convert to 12V until the 60s. Lucas stuff was obviously built until then. Cans of Lucas Smoke are available for refills.
Bare
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If the new/old horn is a 6 volt horn, installing a 12 volt to 6 volt ballast resistor between the bikes wiring harness and the horn will protect both the horn and the wiring harness.
These resistors were used on older cars to reduce the voltage to the ignition coil. Almost any auto supply store will have them.
The only negative about using one is they are usually pretty big and ugly.
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Two resisters (of equal resistance), one in series and one in parallel with the horn and other resistor will divide the voltage in half. Then you'll know you're feeding it a nominal 6 volts. Make one a potentiometer and you can vary the voltage output with the turn of a knob. Makes it reasonably sure you won't smoke check it as Mr. Lucas apparently designed it to do.