2 prong flasher unit (XS2 - 1972)


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Hi all - I am slowly building my street trail bike and want to change the indicators (blinkers) to LED type - from reading the forum there is a lot of information about fitting a new flasher relay, fitting either blown bulbs or diodes for the indicator light in the clock - some of the info seems a bit confusing to an electrical novice, so I after some help

1) - I have a 2 pin flasher unit fitted under the right hand side panel (original one was fitted on the rear mudguard but disconnected)
2) - I have a single amber indicator light in my RPM gauge

The first change I would like to make is the flasher unit - I am going to replace with a LF1-S-FLAT relay which has a Red wire and Black wire - I have a Brown/white connected to ‘L’ and 2 Brown wires which are joined together and connected to ‘B’ on the flasher - can someone confirm which of these wires should connect to Red on the new relay and which one to Black please.

The second change is to fit the diodes to the indicator light - I am going to use these 1N4001 RECTIFIER PROTECTION DIODE - so do I fit one diode to each of the wires going to the bulb holder (blue and brown wires) and if so which way do I fit the please

after doing the above, when fitting the new LED indicators does it matter which way I connect them to the old wiring

thanks in advance for any help


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2 prong works on current flow. with the proper amount of current, it heats up a metal thingie that bends to disrupt the current path and turn off the turn signal bulbs. Then it cools, and makes contact again. If you go LED, the current flow is not enough to heat it up and bend it to disrupt, thus taking a flasher designed for incandescent bulbs will make the turn signal light just come on and stay on. Some flashers will not blink at all if say one turn signal bulb is out and its cold out. There are adjustable LED flashers out there that you take a 3rd lead and then run it to ground (you add the ground wire). Many of them are adjustable with a knob to set the flash rate. Right now, I'm working on an 82 XJ650 that previous owner put one of these in the bike. But the darn thing is voltage sensitive so it flashes at one rate when the bike is off and another when I'm say at 2000-3000 RPM. I have 2 other brands I'm going to try and will report back.

To me, getting a proper working LED flasher that is adjustable for blink rate and is NOT voltage sensitive is the key. Running an extra ground wire is not hard.
Proper LED flasher units will flash at a given rate irrespective of the load on them.
I will add that I had to reconfigure the plug but that was pretty easy as well.
The LF1-S-FLAT relay is meant to be an electronic relay - I got the part number from other posts in the forum - maybe mine is bad ? Not sure how to test it ?