The headlight switch on my 69 Lightning has three positions. One is off and the other two are on, and both on positions have a high and low beam. The two on positions must be different.
It's possible the switch in the bike has been replaced by an incorrect one, and/or the switch in there has been connected incorrectly. Lucas
produced several similar-looking
toggle switches - known collectively as "57SA" - but having different external contacts and internal connections, denoted by a 5-figure number either moulded on the casing or stamped into the plated metal part inside the headlamp shell. Or the bike might have an incorrect pattern switch.
Or the correct original switch has simply gone t1ts-up after nearly half a century ...
So, fraid you'll have to extract it from the shell to know what the five figures are
- you're looking for "31788" or "35710".
Also, extracting the switch from the shell will allow you to identify the terminals by their numbers 1-8, moulded very small on the plastic casing. Then, assuming standard wire colours and you remember to turn the lights on to comply with any 'lights-on-in-daylight' requirement, when reconnecting:-
. the supply wire (Brown/White as standard) from the ignition switch must be connected to terminal #4;
. the Red/Black wire to the pilot bulb must be connected to terminal #6;
. the Brown/Green wire to tail lamp (and speedo. 'n' tacho. lamps?) must be connected to terminal #7;
. the Blue wire to the handlebar headlamp high/low dipswitch must be connected to terminal #8;
. then specifically a 31788 or 35710 switch will:-
.. turn on the pilot bulb and turn off the headlamp bulb when in the "Pilot" position (lever in the middle);
.. turn on the headlamp bulb and turn off off the pilot bulb when in the "Headlamp" position (lever to the right/timing-side); ...
... handy if you want a powerful daytime riding lamp that needs turning off when the headlamp's on, because the bike still has the standard alternator. :bigt
the number for the smaller bulb?
Assuming, by "smaller bulb", you mean the small one in the headlamp reflector(?) - the 'pilot bulb' - first extract the old one from its bulb holder; reason is a p.o. might've replaced the original. However, if you extracted the bulb from the folder by a little push down then a twist anti-clockwise, and it has a single contact on the end, that's likely an original, known generally as "BA9s" - you can enter "ba9s bulb" into your preferred internet search engine and compare the returned images with what you have.
For reference, the "BA" is the abbreviation for "Bayonet" - the push-'n'-twist fitting in the holder, "9" is the nominal diameter of the metal part in millimetres and "s" is the abbreviation for the "single" insulated electrical contact.
You'll see several different-shaped bulbs for BA9s, only don't buy one with a globe larger the metal bit.
Otoh, if you don't find a BA9s, a common replacement is a "wedge"; again, enter "wedge bulb" into your preferred internet search engine and compare the returned images with what you have.
Finally here, answering a question you didn't ask, it's possible to buy and use brighter bulbs than the standard BA9s, for a better daytime-riding lamp. Post again if you want more details.