BMW K-bike Mechanical History

The following information is compiled from the Haynes reference manual and other sources.  If you have any additions to make, please contact me using the link at the bottom of the page.  1984 refers to calendar year 1984, and '84 refers to model year 1984.

1983 - '84 K100 models introduced as the K100 and K100RS, followed later by the K100RT in 1984.

Early '84 UK K100 models...

'84 and '85 K100s...

Early 1985 models got...

Fuel gauge system: The 84-85 K-bikes had self-heating thermistors that are used to activate the low, and reserve indicators. In practice the low light started to come on and off when the tank was just less than full, which was quite distracting. In 1986 the low light was removed.  BMW also switched to a potentiometer that allowed for some hysteresis in the circuit to keep the light from blinking when the fuel sloshed. The potentiometer also allowed the fitment of a fuel level gage.

'85 models...

Mid-1985 models got:

Early K100s... (no date provided)

1985 - K75C introduced as '86 model.  All K-bikes got...

Later in 1985 K75 models got a revised steering head bearing setup (locknut instead of top bolt) and the Fluidbloc damper.

Starting with the K75S in mid-1986, the  fuel tank check valve was replaced by a standpipe on all models.

At some point, fork gaiters were replaced by small air scoops, and the tank was insulated on the bottom.  This was to prevent excessive buildup of heat in the tank.

During 1986...

6/86 (MY87?)

May 1987, all clutch splines have been nickel plated as a precaution against seizure (Walker&Dobson:BMW K-series motorcycles,1989)

Late 1987 K75s got revised anti-backlash gears.  Didn't help :)

Early K100RS mirrors were held in the housings by friction, and later ones by a clip.

Late 1987 modified fork seals used, distinguishable by two external rings

1988 model changes:

During 1988, K100 aux. shaft seal was modified.

In late 1988...

1989 model year

During 1989...

1/90 K75 water pump was revised.

03/91 K100LT production ended. K1100LT production began 03/92 as '93 models.

01/92 K100RS 4-valve production ended. K1100RS production started 11/92.



K11 models got ABS2 and Motronic 2.2 for '94. For '93 they had 2.0, ABS1 and could fit the larger battery.

At some point...

From Joe Dille: "I believe it was the lower left bag mount. They added some additional vibration reducing piece down where the muffler mounts"

K model history