Lighted BMW roundel

This modification was not invented by me. BMW Z4 sports car has these already so if you don't want to see the trouble of making them yourself, they can always be bought from the "Marble desk". The size of the Z4 model is unfamiliar to me so I have no idea how well they would fit in an LT.

I made this modification back in 2007 so most of the pictures are from that time as well. 

Here is the roundel lighted, as well as the " K 1200 LT" chrome bar...

So I started by cutting a correct size round "puck" from a 10 mm plexiglass.

Then I fastened it on a drill in order to rotate the puck for sanding the edge.

The idea is to smoothen the side to matt finsh. Then the light glows nicely through.

Then I used a clamp to place the new ring right on top the original plastic base.

Then I drilled two 3,2 mm holes is my new pucks and made a 4 mm thread in each hole. The new ring will be fastened through these in the plastic base-.

Then is the time to make the larger center hole for the lights. The diameter of the center hole is up to you or depending on what kind of light bulb system you plan to use.

The 4 mm screws come in from the behind. You have to drill a proper size hole in the balck plastic base as well. Your light bulb / leds will be coming through this hole.

Before the final installation I applied some silicone to make a tight seal between the base and my new puck.

DISCLAIMER: 

I built the lights from five orange leds. I soldered their shorter legs together for the ground cable and I had correct size resistors (sorry, I don't remember the size, but if you are familiar with leds, you know how to determine the correct resistor) . These leds did not last for many years so currently I have different light bulbs inside my roundel. I will update the pictures when I have the bike apart the next time (in a couple of months I hope)

Here were the leds

And here I was testing and connecting the positive legs equipped with the resistors.

Here I was testing the final color of my roundel and I realized that it is too white. I need to do something...

I found some orange plastic from my office folders so that was added inside the puck to give more amber light color.

This was the back side of the new roundel. (The lower cables with yellow shrink tubes are for the five leds in the K 1200 LT chrome emblem.

About like this....

In the following pictures I show how I installed the five individual leds in the chrome trim.

At first I covered the chrome with masking tape so it was easier to make the markings on it.

Then I marked the position of the leds. I decided to install five of them.

Here testing the size of the drilled hole in comparison with my leds.

Here I was soldering the proper size resistor in the positive (longer) leg of the led.

I made the connection in such way that each led has it's own resistor so I "stole" the +12V to next led from the front side of each resistor. The negative side was done with the same principle (except the resistors missing). I guess the professionals call this a parallel connection...

Then I added some hot melt glue to keep the leds in place and to protect them from extra humidity. It is good to know, however that the hot air from the radiators tends to somewhat melt the glue so if you ride continuously in hot weather and your fans run often you might want to find another way to keep the leds in place. My leds still work since 2006 but sometimes I can see a small drop of glue hanging down from my chrome trim which I simply peel off...

Of course the removable side panel needs a connector that is disconnected each time the side panel is removed. 

This shows the bike side of the connectors. The white one is for this new led installation and the grey one is for my Hella Micro DE Xenons. They are also fastened to the side panel so both need a connector. I have brought the power (+12V) from my fuse box via a relay and a switch that commands the relay. The grounding of these leds (as well as all my other side marker lights) is done to the bike's turn signal positive lead. This way all my side leds act as turn signals but they go off as the bike turn signal goes on. So they work intermittenly with the turn signals. I hope you get the point...