Flying Brick


Heritage can be defined as something inherited from the past. It is a mixture of history and uniqueness. When it comes to products with heritage, prospective customers buy the product expecting to own a small piece of this heritage. A motor vehicle’s heritage is normally determined by an outstanding feature which over many, many years has come to define the vehicle. Examples of this heritage would be the rear engined Porsche, the aircooled Harley Davidson V twin and the BMW boxer engine. The problem with heritage is that, by definition, it resists change. When a manufacturer decides to replace or significantly modify the product, these changes are never met with open arms by the heritage loving customers. Even when changes improve the design or performance of the vehicle, heritage will obstinately try to block these improvements. Front engined Porsches handled better but sold poorly. Watercooled, Porsche design engine powered Harley V Rods have never really taken off. Which brings us to our featured motorcycle; the BMW K100 with it’s in line four cylinder motor.


The BMW horizontally opposed twin cylinder “boxer”motor has been around since 1923, the first year BMW built a motorcycle. By the early 1980s the boxer’s performance was way behind the Japanese four cylinder‘s performance. Emission control laws were starting to be enforced which the low tech carburettor fed BMWs were never designed to meet. BMW management felt that the boxer design had eventually, after eighty years of production, reached the end of the road. To try and increase performance and lower emission levels would not be cost effective and a new engine was needed to take the BMW brand into the future. To cut down on development time BMW decided to buy in technology rather than develop a motor from scratch. They bought the engine design from Peugeot and in 1983 the BMW K100 1000cc four cylinder was introduced to the world.


To keep the motorcycle narrow the engine was placed longitudinally in the frame with a car-like clutch and gearbox driving the shaft-drive, which also formed the single sided swing-arm. The motorcycle’s center of gravity was lowered by turning the engine on its side, spark-plugs and manifolds on the left and sump on the right. This unusual looking engine soon became known as “the Brick”. The fast, high tech K series received a lukewarm reception from the boxer engine fans but sales slowly began to grow. The heritage-coated boxers still outsold the new K and if BMW thought the boxer engine was to become history, they were very wrong. Today, 30 years later the Boxer lives on comfortably next to the new generation of K engine bikes and the other newer configuration BMW singles, twins and four cylinder powered machines


If you look at a the first series of K100s made from 1983 until 1992, before they were completely redesigned, it takes imagination to see a café racer hiding in its DNA. Yet the imagination of the customiser, like V Custom Cycles who created this purposeful sports machine knows no limits. The first K series café racers were criticised if a round tail or bum-stop was fitted as some felt it did not suit the squareness of the tank. Jaco from V Custom created the tail and seat fitted here to complement and enhance the overall look of the motorcycle.



The stance of the K100 is changed by pushing the forks through the triple trees and fitting the clip-on handlebars . Even the tank badges haven’t escaped customization


The original 4 into 1 exhaust now has a SuperTrapp canister fitted which is aesthetically and melodically sweeter.




Bar-end mirrors fitted to the clip-on bars accentuate the low look of a motorcycle which is surprisingly tall when you swing a leg over the saddle. The large speedo cluster with all the idiot lights has been replaced by a simple small speedo, harking back to the 60s which modern café racers try to emulate. The Brembo brakes are standard


Over the last thirty years the BMW K series has developed its own heritage with its own die hard-fans. Without too much modification or expense the older K series can be freshened up to be part of another great and growing motorcycling heritage – the café racer.

By | 2013-04-25T21:07:32+00:00 April 25th, 2013|Categories: Articles|23 Comments


  1. Green Coffee Advance Diets 30th April 2013 at 2:46 am

    Thanks for finally writing about >BMW K100 Cafe racer <Liked it!

  2. politbike 3rd May 2013 at 8:57 am

    good looking K 🙂 where did you get the speedo? how easy was it to fit with the K’s complicated electronic speedo drive from the rear wheel?

    • retrowriteup 3rd May 2013 at 5:24 pm

      send a email to Jaco from V-customs, he would be able to assist

    • Ales 17th January 2014 at 10:02 pm

      If you look at the close up of the fork you can see the external pick-up speed sensor.

    • Andres 12th August 2014 at 6:16 am

      Where you ever able to get any information in regards to the speedo? Any one that might have information on this?

  3. David 26th May 2013 at 8:21 pm

    Oh my. BMW K100 Cafe racer was a good read!. Beautiful.

  4. Roger 30th May 2013 at 6:07 pm

    This is the most beautifull k 100 CR I have seen for years.
    What color is it? Exhausts?
    Best Regards from Switzerland

  5. retrowriteup 4th June 2013 at 12:11 pm

    As far as I know, the existing headers have been modified with a Supertrapp. Its a satin Titanium/Gray and Black colour. V-Customs could assist you with more specific details.

  6. Gopher 7th June 2013 at 9:28 pm

    The big advantage of your naked design is no-fairing allows clip-ons. Note that clip-ons put the controls ahead of the forks so that the clutch cable clears the fork tube.

    I wonder how comfortable moving the controls down and forward almost a foot is without rear-sets. I have fitted both BMW and Raask rearsets to my K75S. I like both of them for different design features.

  7. Joe Medley 2nd December 2013 at 5:44 pm

    What year model is the bike shown above? Love the look and I’m thinking of building my own.

    Thanks for your time.

  8. Polarman 1st January 2014 at 6:34 pm

    Beautiful project. I am doing a conversion on my 1984 K100RT and will use yours for inspiration. Thank you. BTW: where/how did you source the 4 into 1 exhaust so you are able to use the lovely Super trap?

  9. JanMT 26th March 2014 at 1:54 pm

    What kind of tire dimensions are on this bike? They dont seem standard…
    I am trying to find some preformance tires for my K100…
    BTW: This is the best looking K100 I’ve seen so far.
    Thanks for the reply in advance…

    • retrowriteup 26th March 2014 at 11:35 pm

      Those are Bridgestone Spitfires, rear tire looks like an 130.
      Hope this info helps.

  10. Marria Bennink 14th April 2014 at 9:49 pm

    Is the seat handmade or where can i buy one?

    • Aaron 16th July 2014 at 10:52 am

      I am likewise interested in the rear faring / seat, hoping to buy I’ve rather than make one.

      If you have some details that would be awesome, cheers

      BTW – best k100 racer around, classy mods!

  11. Kev 24th April 2014 at 7:43 pm

    Great looking machine I’m building one myself and got some great tips from yours and was just wondering where you have mounted the ignition barrel as I can’t see it on the pictures? Thanks Kev.

  12. Luis Etchenique 23rd May 2014 at 6:17 pm

    Love it, and in the market as of now looking for a donor bike to do a similar project. Will be asking for your help pretty soon…!

  13. Lars 9th October 2014 at 2:58 pm

    Great looking K100. This is the first time I see a k100 café racer project with all the right proportions. Love the color choice.
    I am building a K100 café racer myself and I am interested in the color of the cylinder head cover. Can anyone tell me what color this is (perhaps RAL-code) ? Thx!

  14. Pete 12th October 2014 at 2:12 pm

    Where you got that little fairing below tank (cooler cover)

  15. Bjenke 25th March 2015 at 11:47 pm

    Super never see a nice 83 k100 like this
    Im building it myself richt now at this moment
    And use the perfect pictures of this site
    Do you have any color paint numbers for me
    Becoise im trying to copy this suPer model you create
    From bjenke nederands. Holland
    If you like to have pictures of mine whe can send ofcause

  16. Dimitrios 12th April 2015 at 2:52 am

    Great write up and bike. I would love to get the parts list from this built. The clip ons, speedo, tail. Where to get them from. I have an 84rt. Also, would be nice to have a k100 cafe racer group somewhere

  17. Nuey 8th November 2015 at 10:10 pm

    Beautiful bike. I’ll go over your article again more carefully and build my own.

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