For this to work it would need to be the brake light which flashed. If it was the tail light which flashed that wouldn't be very visible with the brake light on steady, The flashing of the brake light would be more visible if the tail light on that side was extinguished while signalling a turn. I think that this could be accomplished using a couple of relays.OG taillight would remain. Instead of it only getting brighter when brake is applied, a on/off to one half of the tail light would happen when turn signal is on.
Check out the ones from Speed Moto I linked above.I've considered replacing the ugly Custom taillight with a pair of lights on the sides. Using front signal assemblies with red lenses could give the same tail light/brake light functions. Placement would need to be carefully considered.
I like the stock parts too, that’s kinda why I was asking if there was a way to integrate the dual purpose of the newer tech into the original parts.I don't like the one-piece ANKIA unit, but the pair from Speed Moto is OK.
For the build I'm considering, I liket the look of period parts, so I'd want to use the stock signals. I think there are red lenses available in the aftermarket.
Good point. It would not be legal for turn signal only. 4” is what I found.In the UK the L and R indicators must be at least 240 mm apart (I think, or something like that) to be road legal on a motorcycle. I guess putting the indicators in the rear light housing would not achieve this, would it? Aren’t there similar rules in the USA?
What transistors would be needed?Watch out with putting relays into the brake lights, they aren't fast enough and every moment counts when it comes to warning people behind you of your intents. I'd want to rig it up with a couple transistors instead as the delay would be minimal. Or rig it so the relays are on normally, so the brake light works at normal reaction time, but the relay can cut one side off in sync with the flasher. IIRC some study was done and they found the cars with LEDs which light up faster than traditional bulbs statistically were rear ended less often, so the speed of the light turning on is already slower than optimal.
Here is an example of a relay that may work well for this, it has both normally open and normally closed outputs and costs a couple dollars. Definitely a bit overkill in terms of amperage tho... https://www.mouser.com/datasheet/2/315/Panasonic_05172021_Relay_Automotive__TE_Series_-2326578.pdf
Found a decent writeup on relay designs here http://autoshop101.com/forms/hweb2.pdf
Depends on how you run it but a couple mosfets as are probably the way to go - main consideration is that they have the ability to dissipate the power requirement of the bulb. You'll want to run them in "switch mode" as if they weren't linear devices. Here is a quick tutorial on it but I recommend both learning more about these things and building some test systems before bolting anything to a bike, since the brake lights are sort of critical for safety. https://www.electronics-tutorials.ws/transistor/tran_7.htmlWhat transistors would be needed?