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1Back to top Go down   Front headlight relay modification Empty Front headlight relay modification on Fri Jun 14, 2019 6:26 am

StefanMajonez

StefanMajonez
active member
active member
Hi!

As always, if you have any comments, see any errors or would like to add anything, feel free to do so!

Roughly two years ago, I've seen some people recommend splicing some relays inbetween the switch and the bulb. So, I thought to myself "this is easy!" and proceeded to do just that. But, midway through I suddenly realized it's not that extremely easy, but since I already cut some wires I haphazardly threw everything together, until it worked. It was a right mess of jumbled wires and relays just hanging around the front of the bike, and once every 4-5 months some wire came loose and I had to repair it.

So, I decided to do this properly this time.

First, let's look at the electrical box under the tank.
Front headlight relay modification X3HZXHd
On the bottom-right you can see the starter relay, which has a direct connection to the battery. We'll be using that.

But first, consider some basic safety:
Front headlight relay modification On6ym2n
Front headlight relay modification Ire3q3H

This is how I tied this to the starter:
Front headlight relay modification IagbEqM

Now that that's done, let's think about routing the power cable to the front of the bike. This is how I did it, it was mainly trying and prodding into where the cable would go and fit. The most important thing is to properly route it around the steering column, ideally you don't want that wire to move at all when turning. It's no fun when the isolation wears off and the cable shorts to ground, blowing the fuse and leaving you in the dark.
Front headlight relay modification ZAePu8f
Front headlight relay modification Zv6xGpF

You can barely see, but this is a photo of the left side of the steering column:
Front headlight relay modification BJ6EOwm

And this is from the right:
Front headlight relay modification SmeNlmt

Finally, we're at the front
Front headlight relay modification YX1GyMQ

Connecting it back to the electrical box:
Front headlight relay modification Nj1IJ0g
Front headlight relay modification NmlfE1T

Now, to the slightly more intricate wiring. Back in the day I cut the OEM cables rather short because I wanted to use the original H4 bulb plug, which was a mistake because you can buy those for basically nothing. But, since I did, I had to make those cables longer:
Front headlight relay modification DeI56y0
Whenever I connect the wires like this, like the OEM to the new blue wire, I do a lineman's splice , and solder them together for good measure.

I bought those relays and mounted them right under the cluster:
Front headlight relay modification FRC7A-S-DC12V
Front headlight relay modification JUsgrMb
The two pins on the left are for the electromagnet, the two on the right (next to the white ziptie) are for the contacts.


Front headlight relay modification TQWSsZY
Now, on this image you can see two things. First, I connected the blue 'OEM' yellow, white and brown(black) wires to the electromagnet pins, and then I checked if everything works correctly - turn the key and turn the light on and off, you should hear and feel the relays clicking.
Secondly, the power wire needs to connect to all of the relays, so I made that wire splitter, also seen here:
Front headlight relay modification M8K7cAO


Here's how everything looks put together:
Front headlight relay modification 5jImJGm
The blue wires that are plugged to the left side of both relays are the extensions of the OEM white, yellow and brown wires. The red wires with black heatshrink, that are plugged into the middle of the relay, are the power cable splitter. Finally, the red cable plugged to the right side of both relays, both colorcoded either white of yellow, are just wires that will go straight to the bulb, as you can see here:
Front headlight relay modification Qq0FUbV

Everything is connected, the bulb has rather long wires for ease of replacement on the road, I tested everything out and it works marvelously.

One thing I forgot to mention (and forgot to take photos of) is that black wire going to the light bulb. That's one end of it:
Front headlight relay modification HX3xVNE

Right under the gas tank, near where the frame meets the steering column, there's a bolt that acts as ground. That end in the above photograph is bolted there, and the cable is routed basically right next to the red wire. Then it's connected straight to the bulb.

That's how that works with the front put back on:
Front headlight relay modification I5GfCPh
Everything ziptied in place, no major cable mess, I would consider that a success.

And that's how the relays sound like:


__________________________________________________
1994 - BMW K1100LT
Dyno results 2017


Previous bike:
1989 Honda CB450S
    

2Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 7:38 am

Dai

Dai
Life time member
Life time member
Only one comment Stefan: it looks like you've used something in the region of a 28/0.3mm (25 amp) cable). A piece of 16/0.2mm (11 amp) cable would have done the job and might have been easier to thread. OTOH if that's what came attached to the fuse holder then just ignore me Very Happy


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

3Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 8:06 am

StefanMajonez

StefanMajonez
active member
active member
@Dai wrote:Only one comment Stefan: it looks like you've used something in the region of a 28/0.3mm (25 amp) cable). A piece of 16/0.2mm (11 amp) cable would have done the job and might have been easier to thread. OTOH if that's what came attached to the fuse holder then just ignore me Very Happy

That's a very good point, and was what I was using earlier, but my plan is to add one more relay and add two auxiliary LED lights to my bike, which would be 40W each. That's 6 amps more, which added to ~4 amps used by the regular bulb starts getting close to 10 amps, so I decided to get a thicker wire. These:
Front headlight relay modification Lihgt10
I've seen them in real life and, while not being absolutely perfect, they actually do more or less send light in a rather flat, horizontal line. And they cost €50 for a pair. I'm looking for some more light during nighttime while at the same time not necessarily blinding other people.

Also, you'll love this:
Front headlight relay modification UnBGv3v
Front headlight relay modification D6OIf4g
A tiny little blue button that fits perfectly into a hole in my left handlebar assembly. It's not wired yet, but when I get the lights and another relay I'll wire it up so that the button will glow blue when activated.


__________________________________________________
1994 - BMW K1100LT
Dyno results 2017


Previous bike:
1989 Honda CB450S
    

4Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 9:24 am

Crazy Frog

Crazy Frog
admin
admin
The big advantage of keeping the original H4 socket is that in case of problems, the circuit can be easily reversed to the original state.
Front headlight relay modification Headlight-upgrade1


__________________________________________________
Front headlight relay modification Frog15Front headlight relay modification Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

5Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 10:54 am

StefanMajonez

StefanMajonez
active member
active member
@Crazy Frog wrote:The big advantage of keeping the original H4 socket is that in case of problems, the circuit can be easily reversed to the original state.
Front headlight relay modification Headlight-upgrade1
It's the first time I'm seeing this diagram, and I have to say it looks rather elegant. One question though - how hard is it to find the White/Yellow cable?


__________________________________________________
1994 - BMW K1100LT
Dyno results 2017


Previous bike:
1989 Honda CB450S
    

6Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 10:57 am

duck

duck
Life time member
Life time member
@Crazy Frog wrote:The big advantage of keeping the original H4 socket is that in case of problems, the circuit can be easily reversed to the original state.

+1


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

7Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 4:26 pm

Dai

Dai
Life time member
Life time member
Don't know about Poland but

http://www.vehicle-wiring-products.eu/

Any colour(s) you like.


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

8Back to top Go down   Front headlight relay modification Empty Re: Front headlight relay modification on Fri Jun 14, 2019 7:23 pm

Crazy Frog

Crazy Frog
admin
admin
@StefanMajonez wrote:
It's the first time I'm seeing this diagram, and I have to say it looks rather elegant. One question though - how hard is it to find the White/Yellow cable?
THe white /yellow wire is the one going from the left to the right handlebar controls.
Check this page and click on the "lights" tab


__________________________________________________
Front headlight relay modification Frog15Front headlight relay modification Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

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