Fitting LED Indicators to a Royal Enfield Motorcycle
How to switch over to using LED indicators and Flasher unit.
I had a problem with bulbs continually breaking. I don't mean blowing here, but the filaments just seemed to drop off. I don't know whether it was poor bulb quality or just vibration but I switched to an all LED setup. But not without some trouble.
Firstly I fitted an Combined Rear and Stop LED. No problems. Then I made four indicator bulbs made by adding many LED's to the base of an original buld (not forgetting to add resistors as current limiters). When these were fitted the flash rate was all wrong because the internal resistance of the bulbs were different to the old ones. The bi-metalic strip in the flasher needs to have current drawn through it so it will operate properly. I sorted this by fitting large resistors to the backs of my bulbs.
But this defeats the object really. Ok so the bulbs didn't blow but I want to save power as well, right?
Next I buy an purpose built LED flasher. I fitted this and the indicators worked well. I then removed all those big resistors thinking 'Hey, no bi-metalic strip, no need for these things.' How wrong can I be? I switched on the indicators only to find they came on like Hazzard lights. They all flashed! Hmmm.
I studied the wiring schematic and asked a few friends (Nick actually) who pointed me in the right direction. The 2 watt Indicator bulb in the speedo is joined across both sides on the indicator wiring and pulling its earth through the opposite bulb. This doesn't light up the old filiment bulbs as they are unable to get enough current. But. BUT! The LED's don't need much current and will work on this little amount.
I removed the speedo and pulled out the 2 watt bulb and Hey Presto! The indicators worked like a dream. This 2 watt bulb was never bright enough for me anyway and I have since added another LED to do this job for me (with diode protection).
Hopefully that will help you if you decide to go the same way I did. I'm told many older bikes use this kind of circuit. Unfortunately, it is too old fashioned for the LED!
Note: I made the LED indicators because they were expensive to buy. Each one has roughly 14-16 LED's wired as follows. One small current limiting resistor in line with 2 LED's.