BMW K bikes (Bricks)

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1Back to top Go down    Winter build over ( for now ;) on Fri Jun 01, 2018 1:33 pm

kenrams

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I just retired so can now concentrate on my bike passions. To this end, I am taking advantage of free local community college access. My local school ( Lake Michigan College, St Joe, MI) received a generous donation and built a technical training school for welding, machining, CNC programming, 3D printing, LASER cutting and woodworking. This just opened last year and it is seriously well stocked with machines of all types and great instructors. 

I decided to try and apply the learning to my 85 K bike. I had resurrected a bike that I had received in boxes a few years ago. I put most of it back together making the usual cafe mods - strip of plastic parts, clip-ons, Acewell, stubby exhaust, polished tank, chopped frame etc.  However, as I started to learn how to machine aluminum and steel on CNC mills and lathes, I started to think about parts for the bike. My first idea was too tidy up the instrument console and this kind of lead me down a path that ultimately led to extensive modification of the the wiring harness. I relocated the battery to create a sense of space and moved all the relays ( eliminating the Bulb Monitoring unit and the Flasher relay ) and fitted a Motogadget M-Unit. I 3D printed a new relay tray which also holds the ICU and new fuseblock. I also found a 92 Kbike that was pretty sick and used it as a donor for wheels, forks and brakes. So I now have upgraded running gear and can fit more modern tires. I think I am going to plasti-dip the wheels as I have seen some great results on friend's cars.   

There are quite a few CNC custom parts on the bike and more in the pipeline. I am working on a set of rear sets right now. I will continue to build/modify custom parts at the college.

I have tried to follow some design build lines that I think are important in any cafe. In my opinion, there should be no gap between the seat and the frame, the mounting hole at the base of the tank should be removed, the angle of the seat unit should reflect the angle of the tank, the headlight should not be too high or forward of the front axle.   

I am happy how it is taking shape but if any of you guys have ideas about things to maybe modify I'd like to hear from you as I am about to start a new semester and I'll need a project after I finish the rearsets Wink

Here's some pics for you.






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1981 r100 cafe- 121,000 miles
1985 k100 cafe - 55,000 miles
    

2Back to top Go down    Re: Winter build over ( for now ;) on Tue Aug 28, 2018 1:36 pm

Brickler

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Uhh… uhm… oh... that instrument console… What an excellent idea.    I might have to copy that idea straight off.


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K100RS ABS 1990
    

3Back to top Go down    Re: Winter build over ( for now ;) on Tue Aug 28, 2018 11:42 pm

TacKler

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Nicely done Ken.  

It is pleasing to see your local community college giving you access to tooling and machinery that is inaccessible to most of us.  I especially like to way the instrument cluster is marked.  Quite stylish, especially the "K100 Cafe".  

Just some questions here, does the single arm holding the speedo pod vibrate?  Also is it mounted on the instrument "billet" with a self tapped hole or secured with a nut on the lower surface?  

With the engine of the K100 being so prominent, I see that the covers you have around the radiator and coil bay are quite square edged.  Would it be possible to have slightly curved/chamfered edges or do thickness/size limitations prevent this?  

The alloy/grey and black colours really do compliment each other.  

Cheers, Dave.


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Red 1991 K75S
    

4Back to top Go down    Re: Winter build over ( for now ;) on Wed Aug 29, 2018 6:01 pm

kenrams

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Hej Brickler,

Feel free to copy - or better still improve! Happy to provide dimensions or more detail if you wish.

I initially started with relocating the ignition key to the handlebar mount hole and used the other hole for a rubber mounted bracket for the Acewell.  After riding it for a couple of months, I decided I disliked the Acewell offset and the idiot lights on it were pretty unnoticeable. So I started trying other solutions until eventually, I came up with what I have now. the funny thing is once you start altering and customizing, you can't stop!

The clearance around the fork leg tops is to give me the option of mounting the clip-ons higher ( and allow a greater "down angle" that will clear the tank).  I am considering covering the fork tops in the next version. I am also looking for a micro battery 12v gauge to incorporate into the unit at that time also.

I vacationed and cycled around Uppsala a few years ago and stayed with my good friends Micke and Morven. At the time I wished I had my K100 though, as the roads are lovely!


Skål!
Ken


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1981 r100 cafe- 121,000 miles
1985 k100 cafe - 55,000 miles
    

5Back to top Go down    Re: Winter build over ( for now ;) on Thu Aug 30, 2018 7:03 pm

kenrams

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G'day Dave,

Thanks for the thumbs up.

The instrument billet piece is mounted via the existing front frame 10mm x1.0 threads as shown below and the speedo does not vibrate (well, there is a point of vibration in 4th gear traveling around 55mph but once you shift into top it is good. The Acewell os mounted via a tapped 10mm 1.0 thread om the "billet". 

 


I also agree with the squareness of the rad & ignition covers and am absolutely going to address those issues. Here is a start, but not the finish! I think maybe I have to make the 0.150 thou slots wider to echo some of the other slots on the casings. I think also I need to echo more accurately the rounded edges of the casings. My background is aircraft engineering - not an artist - and I struggle with design finesse. As I become more familiar with the engineering CNC process of manufacturing, I hopefully can start to apply myself more to the aesthetic design process.  Luckily I have is time to mess about with a fantastic bike Smile.


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1981 r100 cafe- 121,000 miles
1985 k100 cafe - 55,000 miles
    

6Back to top Go down    Re: Winter build over ( for now ;) on Fri Aug 31, 2018 6:55 pm

kenrams

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I spent a couple of days this week working on the rearsets (keeping the stock brake cylinder and reservoir for now). The first test fit is shown below. I think I like the brake side set up more than the gear side though. I'll have a beer or two and think about a redesign (or not).

The footpeg design will be changed next week once I figure out how to use the lathe to knurl the 1-inch aluminum round stock. I don't think that looks too complicated judging by the youtube videos I have seen.Wink I like the ones that BSKSpeedworks sell and will take inspiration from them. http://www.bskspeedworks.co.uk/replacement-parts.html

I am also researching how to make a tool to "punch out" the gear lever splined hole on the new small gear lever.  To make this "spline punch", I intend to make a copy of the splined gear lever by cutting a piece of tool steel using plain indexing on a Bridgeport mill. Should be fun. 



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1981 r100 cafe- 121,000 miles
1985 k100 cafe - 55,000 miles
    

7Back to top Go down    Re: Winter build over ( for now ;) on Tue Sep 11, 2018 2:46 pm

kenrams

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Just finished the resets redesign. I must say that the build -although a bit intimidating -turned out better than I thought it would. It was also much harder than I initially thought it would be. There are lots of design decisions to be made and, as I was working alone, it added time to the process. Fro example, where exactly should the foot pegs be located? How far back. How much higher? What are the correct angles for the brake and gear lever?
I just went for a quick test ride and I must say the feel of the bike has been transformed! It feels much more engaging and responsive. Obviously it will not feel like a modern sports bike, but it no longer feels like a slightly modified tourer - in my opinion.
I think I am done modifying till winter and am just going to ride it for a while.

url=https://servimg.com/view/19238673/32][/url]

    

8Back to top Go down    Re: Winter build over ( for now ;) on Tue Sep 11, 2018 3:05 pm

Chocolate

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Well done, nice details!
I like the overflow bootle, where the battery should be/was.

Go on

Cheers from Germany


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Only a few activities make me experience my senses in a way motorcycle riding does, it is like swimming in the nude in a river.
K75 BA/1992 ABS, K75 BA/1991 noABS, Ducati, Mobylette M1/1973
    

9Back to top Go down    Re: Winter build over ( for now ;) on Wed Oct 17, 2018 4:23 pm

kenrams

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I am starting to think about a winter project and I think I will attempt a rear end redesign. I have always disliked the K bike subframe - it was never designed to be seen yet gets exposed in cafe builds. In my opinion, the up-sloping frame at the seat line is just wrong and destroys the bone line and is why cafe K bikes never look quite right. I understand it is a major undertaking but fortunately, my college has just acquired a CNC pipe bender with notch and fish mouth attachments. Guess the long Michigan winter will be spent sharpening my pipe welding skills ! 

Here is a great, top end K bike that will serve as inspiration. ( from BikeEXIF ). Maybe I might add some triangulation at the shock mount.  


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1981 r100 cafe- 121,000 miles
1985 k100 cafe - 55,000 miles
    

10Back to top Go down    Re: Winter build over ( for now ;) on Wed Oct 17, 2018 6:41 pm

Laitch

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@kenrams wrote:. . . cafe K bikes never look quite right.
Never? Larry Romestant's K/Augusta looks right to me.


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1995 K75T 68,000 miles
    

11Back to top Go down    Re: Winter build over ( for now ;) on Wed Oct 17, 2018 6:52 pm

Dai

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Yes, but that's had the frame modded. Most K-bike cafe racers just look plain bloody awful because no attention whatsoever has been paid to the tank/frame/seat line. Is why I keep banging on about the fuel pump Very Happy


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

12Back to top Go down    Re: Winter build over ( for now ;) on Wed Oct 17, 2018 6:55 pm

Laitch

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@Dai wrote:Yes, but that's had the frame modded.
Most of them have had the frame modded—just not with much ingenuity.


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1995 K75T 68,000 miles
    

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