1. Gather the necessary tools and parts. You will need:
* A Phillips head screwdriver
* A flat head screwdriver
* A new 12V 21/5W stop light bulb
2. Prepare your motorcycle.
* Park the motorcycle on a flat surface and turn off the engine.
* Allow the motorcycle to cool down if it has been recently running.
* Locate the stop tail light. The BMW R1100RT has a single stop and tail light located at the rear of the bike.
3. Remove the old bulb.
* Use the Phillips head screwdriver to remove the two screws holding the stop tail light lens in place.
* Carefully remove the stop tail light lens and gasket.
* Pull out the old bulb from its socket.
* Note the orientation of the bulb before removing it, as the new bulb must be installed in the same way.
4. Install the new bulb.
* Insert the new bulb into the socket.
* Be sure to align the contacts of the bulb with the contacts of the socket.
* Secure the bulb in place by tightening the lock ring.
5. Reattach the stop tail light lens.
* Place the stop tail light lens back in its housing and insert the two screws you removed earlier.
* Tighten the screws until the lens is secure.
6. Test the stop light.
* Turn on the motorcycle and check that the stop light is working properly.
