BMW K bikes (Bricks)

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Silver member
Silver member
I'm posting this on behalf of my friend Phil Moser:
This will be of interest to all K100 owners.

I’ve successfully built a 2,54 ratio ( 33 : 13 ) bevel drive into a K housing using the gears from an R1200C. Standard K100 is 2,82 ratio ( 31 : 11 ), and so it reduces revs throughout all gears by 11%.

It’s made mine VERY long legged, slightly under 4k revs at 120km/h. Another advantage is reduced vibrations. The motor, being very torquey, pulls fine through this ratio. The speedo, taking its input from the rear wheel speed ( not drive shaft speed as in airheads ) stays correct, of course,  and the “spacing” of the gears is not affected as it is in “shorter 1st / longer 5th” as is done by a number of airhead GS riders.

But be warned ! Neither a cheap nor an easy job !

For a more comprehensive article with pictures, see

The link takes you to PDF HOST ... you will see a thumbnail of the article ... click on VIEW DOCUMENT

92KK 84WW Olaf

Life time member
Life time member
I discussed this with a friend who passed in 2021. He was a wizard with final drives.

You can do it on all the K bikes, K1 K75 [if you want] K100 K100 16v and K1100.

If you do it with early K100 you need to change drive shaft to 16 spline.

I have a final drive I had intended him to do for me but he passed suddenly so its not happened.

1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 48,061 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 61,190 miles

1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500


Life time member
Life time member
You could get it down to 2.75 by converting it to a paralever using a  33/12  final drive from a K1 or late K1100LT.

Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT

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