Headlight relay mod - what it does

[Charlie-brm]

It's getting to be S.O.P. to wire in relays for the coils and headlights of any aging motorcycles coming through here. My 1984 FJ1100 was measuring 10.4 volts at the harness plugs from a battery of 12.4 volts. That's only 85% of the available voltage getting the job done. These pictures were taken inside a shop with the lights off, comparing low and high beams and 10.4 volts and 12.4 volts after the relay mod. It's cluttered but that shows the detail the light picks up all through the distance to the far wall shelving in the storage room at the far end. The bulb is a standard Halogen H4.
What ever you are using for a bulb or a lighting system, coils packs, or where ever you buy the relays, this mod ensures you are at least not cheating the electrics of full available power.
My recommendation is to solder every junction where possible instead of using crimp connectors.

[Pat Conlon]

My recommendation is to solder every junction where possible instead of using crimp connectors.

Hey Charlie, yep, that relay mod really works.
The 12.4 volts is resting voltage from the battery, wait 'till that headlight sees the 14.4v charging voltage when the bike is running...

I do have to disagree with you on the soldered connections. I have learned (the hard way) that a *quality* crimp connector is the best.
Quality meaning crimping with a ratchet type tool used in the aircraft industry.
I do tin the wire ends with silver solder first, but a quality mechanical connector is superior on motorcycle applications subject to vibration.

Just my opinion, based on my experience.  Cheers laddie!

[Country Joe]

Charlie,
Very good representation of the difference that full voltage makes to the lights. Now I just have to get off my duff and do the job. I can't say I don't have the parts to do it...

     Joe