Hi,
I am going to try to find some positive earth LED's to mount on a license plate frame
If you buy the holders with two wires, no need to worry about "positive earth"-specific LED. LED themselves are only electrically-different from incandescent bulbs in that LED, like all diodes, only work with electricity passing in one direction, whereas incandescents don't care.
Certainly as standard, your bike already has Red wires connected to battery +ve and the other-coloured wires connected to battery -ve. When you fit indicators, you'll take the supply to the relay from a White wire (all White are connected to battery -ve through the ignition switch but are only 'live' when the switch is on), add a wire from relay to handlebar switch and wires from the switch to the indicators. These'll be connected to one of the aforementioned two wires into the LED 'bulb' holders; connect the other wire to the bike's Red wires; if the LED don't work connected this way 'round, simply swap the LED holder connections to the bike's wiring. :thumb
Up front I know I want to be able to run halogens in the original lens. They are out there with the standard Lucas base.
With apologies to the O.P. for possibly widening the "discussion" beyond indicators ...
Here I assume you mean the headlamp? Ime, this'll be a waste of money for two reasons - original lenses are rubbish and, because the original bulb fitting is BPF - British Pre Focus - the bulbs are only available from specialists, at ridiculous cost compared to a standard automotive halogen bulb.
There are any number of decent 7"-dia. headlamps but, if you're keen not to "change the original lines of the bike", convex lenses with a Lucas logo in the glass are available:-
. From '78, the Co-op started supplying US-market bikes with a headlamp similar to to the one Triumph and NVT'd been supplying the Europeans (except GB) for years before ('79-on Triumph 99-7060, Lucas 54522680).
These take what's known as a
P45t bulb, which are handily still readily-available in both 45/40 non-qh and 60/55 qh. Even the 45/40 bulb will put out a lot more light than a BPF bulb in the original lens, not requiring a new stator.
. However, P45t has been officially obsolete for several years and you might find asking for either of the above part numbers gets you a Lucas headlamp that takes a
P43t bulb; these are only widely-available in 60/55 qh.
The only other thing I can think of is to replace the pilot light with a brighter LED
I've used qh pilot bulbs for years (Philips HMB21 20W) or recently a regular poster on BritBike pointed me at
this (obviously look it up on Ebay.com).
then wiring it to a switch and modulating it.
If your bike has the correct lights toggle switch (35710 or 31788) on the headlamp shell, it switches the pilot lamp separately already (Red/Black wire from terminal 6), because the pilot's off when the headlamp's on and
vice versa. With a modulator with a photocell suggested by Marc, no extra switches? :thumb
Hth.
Regards,