Tag Archives: headlight

Kat Dash BMW /5 LED upgrade install

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I had a wonderful opportunity of installing a Kat Dash /5 LED kit on my customized California blue 1973 R100/5 (yes, it is a /5 with a R100 engine) .

I had the headlight apart already to tighten up the custom key assembly that started turning inside the headlight bucket when I turned the key.

A nice small, tidy box containing the kit arrived in the mail.


The bulbs are labeled nicely in baggies with stickers that indicate the bulb color. I wasn’t sure what the wiring was for and then read the directions and figured it out.

Side note – This bike has the custom key seen here (not a typical /5 nail style key) and LED turn signals that required I wire in resistors to create more  load to activate the turn signal relay.  And, I decided to adapt all the wiring to a /6 style relay board. It all makes sense to me…

But here is what the headlight bucket looked like when I opened it up (spaghetti anybody?).
The gold things are resistors I had that were wired along with the LED turn signals.
One lead of the resister was wired with the positive lead of the turn signal and the other lead of the resistor was wired with the same ground as the turn signal.

R75/5 headlight wiring with /6 Relay board

The Kat Dash kit is pretty easy.
Follow the directions.

BE CAREFUL not to twist the LED’s in the bulb housings too much.  They will come ripped out of the bulb base if you do.

A few things to realize – There are additional wires with resistors added to allow the Generator/Voltage light to activate with the LED bulb.
The same goes for the Turn Signal indicator Light.

I got half way through my install when I hit a major problem – one of the LED lights popped out INTO my speedometer!  Yikes!  This was not any fault of the LEDs.  It had to do with the bulb base being worn/bent too much to hold the bulb in place correctly.  I had to take everything apart, remove the speedometer, and spend about 10 minutes with a tiny magnet until I was able to fish the light out of the speedometer’s rear bulb housing area.

If the bulb sits crooked in the wired base, FIX it before you install it into the speedometer.

 With my 4yr old’s fingers to help me with the photo, I was able to fix it with a dental pick and bend that lip out to catch the bulb better, and hold it straight in the housing… and most importantly, not eject the light into the speedometer housing!

I continued my assembly, and to my surprise, after I wired in the relay to allow for the new LED turn signal indicator bulb to work, I no longer needed my big gold resistors in my wiring scheme.
Kat had sold me an electronic turn signal relay that works with LED bulbs and I ended up not needing it.

Here is the bike off:


Bike with the LED running light on:

Bike with the LED lights on – So bright the gamut of the camera could not capture them:

And a video of everything working:

 

/5 BMW Speedometer Wiring

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Hopefully the following wiring photos can be of help to somebody.
I hope to add to this post once I am done.
Click on the photos for larger versions.

On my last /5 build, I adapted a /6 relay board to my /5. I cut off the terminals i did not need due to the simplicity (and less features) of a /5 vs /6. I also liked the idea of having the fuses easily accessible. Everything works great however in hind sight, I maybe went too far (did I complicate a simple /5 wiring scheme by adding the /6 board?) and perhaps I left the fuses too exposed where they could get knocked out. But I have over 3000k on the bike right now and no issues.
The gold resistors on the bottom of the headlight bucket are for the LED turn signals. Resistors are necessary to adapt the low current draw of the LED’s so the relays still work.
The large black box at the bottom is a /6 /7 and R100S style turn signal relay.
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Here is my naked speedometer. I highly recommend painting the inside of the headlight bucket a bright color. It really helps for seeing inside there.
Labeled
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Here is the speedometer wired. It is hard to see some of the actual terminals/connections but this should be a nice short-cut for somebody who doesn’t want to read the wiring diagram.
Please note: My Red/Yellow wire going to the instrument lighting is also a gray/black wire in most wiring diagrams.
Wires
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UPDATEUPDATEUPDATE
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In hind sight, my /6 relay board wasn’t such a bad idea. I scoured electrical stores, auto stores and the internet for terminal relays and fuse blocks that would work for inside the headlight bucket.
I never really found the perfect solution. I was looking for a nice, compact 2 fuse relay. I also looked for a junction box that suited all the necessary connections.
I ended up using the terminal connector that came with the Rocky Point headlight key conversion (white junction on the right side of the photo).
I also used a CINCH 6 position terminal for wiring up the turn signals, brake light and other connections.

I decided to abandon the typical inline ceramic fuse holders that BMW supplies. The ceramic fuses aren’t readily available at your local auto parts store so I have planned to seek the help of experts from https://telluridetireandauto.com/. And I have also opted for something common like the rubber covered fuse holders carry a typical ATC fuses. BMW specifies an 8 AMP fuse. I went with a 7.5 and a 10 (because that is what i have in my garage). The 10 will be fine. The 7.5 vs 8 shouldn’t make a difference.

The Clymer manual did a great job for most of the wiring.
The other diagrams helped A LOT though. One diagram specified which wires connect to which pin on the turn signal flasher.
One thing that none of the diagrams specify is which terminal numbers on the relays connect to which wire. Yea, a bunch of wires plug into the starter relay, but which wires go to each pin/terminal?
Luckily I took a BUNCH of notes when I tore the bike apart. And luckily the old connections were correct.
Here are my resources:WiringDiagrams
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Here is the headlight bucket as tidy as can be (for now).
WiredHeadlight2
Another iphone quality photo of the headlight:
WiredHeadlight1

After some battery charging, and some testing, and pulling my hair out only to realize that the Rocky Point switch was labeled incorrectly (blue and yellow wires were mixed up and mislabeled). we are good to go!
I popped the headlight on and the bike is showing signs of life again!

HeadlightOnCloseup

HeadlightOn

UPDATE UPDATE – – – –

Here are the photos of the second silver bike’s headlight wiring.  It looks somewhat messy in the photo but take my word for it, it ended up being tidy.  I used a cut down /6 relay board and mounted it inside the headlight bucket.  HeadlightRelayBoard_IMG_4588
 HJeadlightWiring_IMG_4592

Let the wiring begin

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I can’t be happier to have the bodywork back (and my garage back too!). I can finally start putting some overdue time in on the bike. The zen of wiring begins. A part of the build i actually enjoy problem solving.

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Instead of the old, original key switch, we are upgrading to a Rocky Point key ignition. The first step is installing the ‘doughnut’ retainer. You use the same bend-tabs for the ignition board but you bend the tabs on the giant washer instead. This is much easier to install when the headlight is off the bike.

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I then installed the chrome key housing cover. Installing the small spring on the black sliding cover was a bit tricky. That black slider needs to weave into the chrome cover and then you have to wrap the spring around the round tab that sticks out of the center of the headlight bucket. Again, another item easier to install when the headlight is off the bike.
Bending the tabs for the chrome cover is really tricky. An assortment of needle-nose pliers helps.

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The speedometer is simple to install. Don’t forget the rubber gasket that goes between the headlight and the speedometer.
The orange turn signal indicator is simple to install as well.

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Don’t forget to thread the wires through the handlebar switch support piece before you install it into the headlight bucket.

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And so it begins….

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Stripping her down for some pushing

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Title time. I gotta get this baby to DMV to get the VIN inspected and into the ‘system’ so i can get a title.  There is a DMV  1.4 miles from my house (according to google maps). Hopefully they will issue a title there but i have a feeling a second inspection by the Highway Patrol is necessary.  I went through something similar when i put a different engine in my last build.

Unfortunately I’m gonna have to push it that 1.4 miles.  Luckily it is flat.
I took everything off that i possibly could while maintaining the appearance of a motorcycle.  No transmission, no fenders, no seat, no tank.  She’s actually pretty light after all that stuff is off.
And thankfully the tires still hold air.

Stripped down R75/5

Stripped down R75/5

The Clock