The K75RT, K100RT, K100LT, K100RS, K1, K1100RS and K1100LT all have the same headlight assembly. It is unique to K bikes and not used on any other vehicles. It mainly consists of a reflector and lens:

    

 

The Bulb:

All K bikes use a standard H4 (a.k.a. 9003) dual beam headlight bulb easily obtained online or at an auto parts store. (I use LED H4 headlight bulbs in my Ks these days.)

Looking from behind, this is how it is wired:

Changing The Bulb:

CAUTION: When dealing with H4 headlight bulbs be very careful not to touch the bulb glass with your fingers. If you do then the natural oil on your fingers sticks to the glass. When the bulb gets hot (and they do get very hot) this oil will heat up and can cause the bulb's glass to break. If you do accidentally touch the glass then clean the bulb off with something like rubbing alcohol before installing it.

 

This first things to do are to 1) pull back the rubber boot and 2) wiggle the connector to remove it from the back of the H4 bulb.

 

BULB RETAINERS - There are two mechanisms used to hold the bulb in place. Early K bikes have a "locking ring" and later K bikes use something that I call a "squeezable spring."

 

Locking Ring - The locking ring needs to be rotated counter-clockwise in order to remove the bulb. Once rotated about 40 degrees the ring will come free and allow the bulb to be removed.

Installation is the reverse of removal.

If you lose the locking ring or are missing it for some reason the BMW part number to replace it is 63121459470.

 

Squeezable Spring - Push in and squeeze as shown below. The spring can then rotate over to the left to release the bulb.

 

Adjusting Beam Direction:

LEFT/RIGHT - Turn the knob clockwise to adjust the beam towards the left or counter-clockwise to adjust the beam towards the right.

 

UP/DOWN - There are two mechanisms for adjusting beam height: a white lever for macro adjustments and a black hex knob for fine tuning.

The white macro lever has three positions: up, middle and down. This is handy for quick headlight adjustments when you have changing loads. e.g. Riding solo with no luggage vs. riding 2-up with full luggage. Up is the highest  pointing beam and down is the lowest.

Turning the black knob clockwise lowers the beam and turning it counter-clockwise raises it.

 

© 2021 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.