How-to (new) - Fazer8 dual low beam mod (WIP)


New member
Yep - the factory low beam is single filament.

As we have discussed, you could do this mod much more simply just by hooking up the green wire directly to the low beam on the dual-filament side. That will work perfectly and can be done in just a few minutes.

I did it this way because I was unsure of the exact wiring of the lights & what the impacts might be of the additional load on the circuit. Turns out to be a non-issue based on what other folks here have told me.


New member
The reason i have been told by a friend that designs custom motorbikes is that sometimes dumb cagers can mistake a motorbike headlight with dual lights to be a car in the distance, when in the real world its a motorbike at close distance. so some manufactures choose to put single lights on rather than dual.

Fazer 8

New member
I think I would like to do this, as I feel the extra light at night would be welcome. I do find the headlight a bit weak after my last bike, a Suzuki V-Strom. It had two 55/60w beams which both operated together (just like a car). I don't know why Yamaha didn't go that way - I guess it might require a little more alternator output, slightly heavier wiring and switches. Or maybe it was just that they didn't want to have to change the switchgear and such from the FZ8 for the Fazer 8. I guess this way we do have one unit optimized for low beam and one optimized for high (if you look carefully the reflectors aren't quite the same), but I'd rater have a full 110/120 w of lighting rather than the 55/115 that we get on the Fazer.

I see now what you were talking about - the left hand light only has a low beam bulb, and the right is only using the high, although the bulb has the low beam filament as well. I hadn't realized that - so the left hand low beam always stays powered. Is its power even routed through the high/low switch? Or only through the headlight relay? I guess I really need a wiring diagram for an FZ8S, rather than the one for the FZ8N (which I got as part of a downloaded service manual).

If I understand what you guys are saying, the low beam wire coming out of the switch is not being used? In which case, it's no brainer to hook it up, and doing so shouldn't result in any heavier of an electrical load on anything than when running the high beam. The switch and the wires from it to the headlight would be my worry otherwise - as to whether they were sized to handle twice the current as usual, but if the left low beam isn't going through it, it's not an issue.

Oh, and as to why there might be an unused low beam wire coming out of the switchgear: I suspect it's because Yamaha used the same switches, including the attached wiring, on both the FZ8 and Fazer 8. On the FZ8 that wire is connected in the main wiring loom to the low beam wire of the part of the loom that connects to the headlight. I'm guessing that on the Fazer the green on black wire in main loom headlight connector is instead connected directly to the headlight relay, same as the wire that feeds power into the headlight switch.
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New member
Yeah - that is my understanding. The switch is basically switching power between the low & high beam of the FZ8, but on the Fazer it is only hot in the high beam position (no connection to low beam) but the wiring is the same. So, there would be no more load by doing the mod the "simple" way than there would be when running the high beam (less probably...).

I did the mod before I fully understood that, and I wanted to be sure I wasn't adding extra load to another circuit. However, it was a good exercise and the same approach could be applied to adding auxiliary lighting (driving lamps, fog lamps, etc) triggered from the high/low beam switch (or an add-on switch). The only question then would be the alternator's output.

Fazer 8

New member
Cool. I think I'm going to trace the switchgear wiring harness back to its plug and make a cut in the wire near there.

I'm also looking for a good switched power source for my GPS hardwire power supply and some heated grips that I've got. Looks like I may have to do my own, because it looks like the existing circuits which have relays also have fuses before the relay, and presumably they are fused and sized just for their intended loads. The GPS power supply is fairly trivial - on my last bike I had it hooked up to a tap into the taillight wire - only uses about 1 amp. The heated grips need somewhat more.


New member
Hi guys,

I was planning to do this mod.
Could someone confirm if its the green wire that I have to connect the H4 low beam to.

The snaps in the original post isnt visible any more, hence am a bit unsure.
Thanks in advance.

9 Lives

New member
I am not sure why Yamaha went this way on the FZ8, the FZ1 has a high and low beam filament on both sides. Both sides light up on low and high beam just like a car. I sold my FZ8 a couple of years ago and bought a FZ1. I did the mod on the FZ8 because I got tired of ppl telling me I had a burnt out headlight.


New member
On the sport bikes with the dual lamp set up, you just ride with the brights on and both lights will always be on. At night time, I guess you may need to be turn off the brights but I am not sure it really matters unlike a car. It definitely helps people to see you


New member
Hey all,

Late to the party on this one, I am wanting to complete the dual dipped headlights, from reading this post it seems the *simple* version should be a fine way to go.
Whilst I see it mentioned often and talk of a green wire I cannot see the original post.

Maybe it will be really clear once I start pulling faring off, but if anyone has the original post or a rundown it would be appreciated.