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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Woytas on May 21, 2025, 03:13:12 PM

Title: Crash bars - missing bolt K75C '93
Post by: Woytas on May 21, 2025, 03:13:12 PM
I bought used crash bars for my K75C '93 and realized that one bolt is missing, I've got only this one:

(https://www.motobrick.com/gallery/4/8346-210525150331.jpeg)

While looking for the missed and I found two different ones:

https://www.bike-parts-bmw.com/bmw-motorcycle/K%20100/1989/K%20100%20RS%20(0523_0533_/K589-05230533-/Frame-and-mounting-parts/Engine-protection-bar/9/46_1274/46/517080523

46 71 2 303 080
https://www.bike-parts-bmw.com/bmw-motorcycle/assignment_spare_parts/46712303080

46 71 2 303 079
https://www.bike-parts-bmw.com/bmw-motorcycle/assignment_spare_parts/46712303079

The first one is on ebay in Germany, so I could get it quite easily - https://www.ebay.com/itm/123756556530


Could you please help which one I've got and which I have to buy?

Many thanks in advance!
Title: Re: Crash bars - missing bolt K75C '93
Post by: Laitch on May 21, 2025, 05:44:19 PM
A screw is usually measured from the tip of its shank to the base of its head. Maybe that is what you're doing; the 2mm mark is perfectly aligned with the base of the head.

You've provided a diagram and parts list for a K100RS 4-valve Brick. Your Brick's screw shank measures 85mm which is the correct shank length for the crank side protection bar screw of the K100RS 4-V. Please verify the model and year of your Brick. If your Brick is a K75C, consult the correct parts fiche diagram and list.

In the USA, MaxBMW's parts fiche (https://www.motobrick.com/index.php?action=post;topic=16016.0;last_msg=142177) and Bob's BMW/Ducati show the screw shank length for the screws on both sides of a K75C as 65mm but their head designs might differ because their part numbers differ.

Somebody who owns a K75 and has installed these contraptions—regardless of their effect on engine protection—should chime in.
Title: Re: Crash bars - missing bolt K75C '93
Post by: Woytas on May 22, 2025, 01:03:00 AM
A screw is usually measured from the tip of its shank to the base of its head. Maybe that is what you're doing; the 2mm mark is perfectly aligned with the base of the head.

You've provided a diagram and parts list for a K100RS 4-valve Brick. Your Brick's screw shank measures 85mm which is the correct shank length for the crank side of the K100RS 4-V. Please verify the model and year of your Brick. If your Brick is a K75C, consult the correct parts fiche diagram and list.

In the USA, MaxBMW's parts fiche and Bob's BMW/Ducati show the same screw shank length for the screws on both sides of a K75C as 65mm.

Somebody who owns a K75 and has installed these contraptions—regardless of their effect on engine protection—should chime in.

Good point! I've seen so many of these diagrams. In K75/3cyl both screw have the same length https://www.bike-parts-bmw.com/bmw-motorcycle/K%2075/1984/K-75-85-0562_0571_/K569-05620571-/Frame-and-mounting-parts/Engine-protection-bar/9/46_1274/46/517380562 (https://www.bike-parts-bmw.com/bmw-motorcycle/K%2075/1984/K-75-85-0562_0571_/K569-05620571-/Frame-and-mounting-parts/Engine-protection-bar/9/46_1274/46/517380562) so I need two 46 71 2 303 080.

Many thanks!