Category Archives: Motorcycles



This is a German late 1970s Zundapp Famel. The company went out of business in 1984. From Wikipedia I found that Xunda Motor Co., in Tianjin, China bought the intellectual rights to the company. They produced small Zündapp motorcycles from 1987 till the early 1990s. Zündapp is still in business, but makes Honda based 4-stroke motorcycles and electric mopeds.


This 1930s motorized bicycle was built by the French company Terrot in Dijon France. This was spotted in a store front window in Seville Spain. I like the golden flared exhaust pipes.


I don’t know much about this “Monkey Bike”. If you go to the URL printed on the front fork of this bike you will end up at a Spanish importer of bikes. I’m guessing this is a 110cc Honda. This was found on the streets of Seville.


This is the first Portugese brand of motorcycles I have heard of. Apparently Macal produced a range of models with 2-stroke as well as 4-stroke engines.. They bought their engines from various suppliers including Honda. This bike is in active service. Notice the left hand side kick start on a concentric shaft with the gear shifter. Macal was founded in Portugal in 1921, and ceased production in 2004. This was spotted at the farmers market in Lagos Portugal.


This late 60s early 70s British looking motorcycle is actually a 2013? Chinese Mash 125. Why they label it “Seventy Five” I don’t know. They even put a British flag on the side and all the printing is in English. This was spotted in Ronda Spain.  Dave


Vintage bikes and design experiments

One more vintage bike, this one a Bultaco


Playing with Rhino to design a motorcycle fairing. The rider will lay on this bike with his head even with the handle bars and feet behind the rear wheel. The nose section above the front tire is a clear Lexan windshield.


Using OpenFOAM and ParaView to analyze the aerodynamics of a motorcycle

I have a friend in Tacoma who is building a motorcycle with the intent to break a speed record this year in the Utah salt flats.  His name is Mike and here is a link to  a blog that chronicles his efforts.  He even gave me a little shout out for helping with some curve coordinates.   Mike built a bike to race last year but weather prevented ever running it on the flats.  Mike has been doing a phenomenal job all after work and weekends and I applaud his efforts.  I wanted to provide more significant help but the timing of this trip precluded me adding any value.  Never-the-less the idea got me interested in learning more about how to use my computer aided design application Rhino (a very popular CAD package from Robert McNeel & Associates headquartered in Seattle).  I spent some time leaning how to create airfoil sections curves and surfaces.  The example above is the result of some of those experiments.  Next I wanted to figure out if I can analyze the aerodynamics of a bike.  Aero analysis is performed with CFD (Computational Fluid Dynamics) software.  Most of the good CFD software costs $10K or more.  I found a fairly good free (open source) application called OpenFOAM and a second application for viewing the results called ParaView.  I am continually amazed at the amount of free quality software that is out there.  CFD analysis is fairly complex and software to perform it complex as well.  Luckily OpenFOAM comes with a bunch of test cases one of which happened to be a motorcycle.  Even with the support of having a ready made test case it still took me 20 to 30 hours to get to the point of being able to produce the image above.  The colors represent air pressure, red being high pressure and blue being low pressure.  The squiggly lines represent how air would flow.  My next experiment will be to take my draft motorcycle above (second picture), add a driver,  and perform the same aero analysis you see in picture three.  I hope at some point I can take the real shapes of Mike’s motorcycle and run it through this software to see the results.  Since I have only scratched the surface of leaning how to use the software, I have a bit of work ahead of me.  Luckily there are lots of good tutorials out there and there is a complete course from MIT on aerodynamics that I have been viewing as well.  My major is Electrical Engineering (not aero) so all of this is new to me.  Now you know what occupies my time for 9:00 till midnight.  (Loren – this is why a lug a computer around).  -Dave


Vintage Motorcycles

IMG_1433 IMG_1825 IMG_1875Laura really likes shopping at the vintage shops so I thought I should follow suit and do some vintage shopping of my own.   I’m not sure if these will fit in my suitcase but I think I will try.  I owned a Norton 850 Commando for many years so the Norton would be a good choice but I think the Moto Guzzi would draw more attention and I suspect is a more rare bike.  Scooters are the most prevalent bikes here in Spain but there were a significant number of old motorcycles on the road in Malta.   — Dave