If you're reading this page, you're probably wanting to change your shitty lightbulbs into hot sexy LED bulbs for some reason like wanting to turn your moped into a spaceship.
If that sounds like what you're trying to do, you're on the right page! Below is a general guide on doing an LED conversion for our anachronistic, vintage mopeds.
General Information / Before Starting
General information on LED technology can be read at the LED Technical Specifications document. This is not required reading, but if you're curious, it's highly recommended.
In short, LEDs are Light Emitting Diodes. We get the first two words, 'Light emitting', in that they're like a lightbulb. The important distinction to make is actually the last part. 'Diode'. A diode in a circuit is a component whose function is to allow electricity to flow one way.
LEDs have two pins, usually. The first and longer one is the 'input' where electricity goes to flow through, the shorter one is your 'output' which would go to ground or something similar. If you were to put the LED in backwards, it actually wouldn't do anything except maybe burn up instantly. This is because LEDs block reverse voltage/current up to their rating, and when it exceeds that rating, they burn.
This is the most common reason why LEDs fail on Mopeds. The usual moped in the wild has an unregulated AC electricity system. I won't go much into AC/DC (highway to hell). But, in AC electricity follows a sine wave curve where it goes backwards and forwards usually about 60 times a second. Before AC, there was DC, which is electricity that flows just one way in a circuit.
LEDs are designed for a DC circuit. I mentioned before that they're a diode, and so regardless of which way you hook them, they'll light up about 30 times a second on an AC circuit. Unfortunately, LEDs really fucking suck at being diodes. They're horrible at it. They have low ratings for reverse voltage and will burn up in no time. LEDs also hate being over-volted, and it will short out their lifespan by a lot.
So how do we fix that?
Design Problem / Thesis / Solution
So the problem we face is that we need to supply the LEDs with DC electricity, and it needs to be a certain voltage or we'll break them!
Sucksors. How do we do that?
Well, it depends on what you're trying to do. If you're looking to change your taillight to LEDs and already have a circuit, the easiest and quickest way is to buy some diodes (that aren't LEDs. These are commonly called rectifiers) and just solder them right into the ground of your taillight between the LED board and the wire. That diode will take the reverse current/voltage load off of the LEDs and it's /designed/ to take that kind of abuse. Your LEDs will flicker, but they'll be much happier and actually function. Their voltage will still be unregulated, though. This might not be an issue, but the life of your LEDs will likely be less.
The other solution is to convert your whole bike's electrical system to DC. This is done most commonly by ordering a Trailtech regulator/rectifier. Not only does this solve the issue of rectifying the electrical system for your LEDs, but it also regulates the voltage for the whole bike, preventing it from going above a certain voltage.
Doing this is different for each bike, so I can't exactly cover that all here.
Feel free to add more things here