DOUGLAS MOTORCYCLES


(Variously known as 'The best twin'; The Vibrationless Twin; etc.)


Contents:

My 1948 Mark III - The early years

I found my 1948 Douglas Mark III in a back yard in Welwyn Garden City (England) in 1965 - prior to my 16th birthday.  (bought as a non-runner for £3-0s-0d - I still have the receipt). I must have had it running about 15 years total since then.  I got it going and rode it for many years in England - In Hertfordshire as a teenager, in Cambridge as a student, and when I lived in Oxford 1976-1980.  The trip to the Isle of Wight 1970 was about 200 km each way.  It was there that Jimi Hendrix played his last public performance. 
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Figure 1:  In Welwyn Garden City c. 1967.

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Figure 1:  At the Isle of Wight Festival 1970.


My Mark III - Recent

 
The bike was shipped to Vermont in 1980, when I moved here.  I ran it every summer (wet snow plays havock with the exposed ignition system) until 1991 when my priorities seemed to change.  After about ten years of sitting in my basement, it seemed like time to get to work and get it going.  I did steadily get some work done on the front forks, general paintwork clean up, steering head, wheel bearings, clutch thrustbearing, etc etc.   I was out of action for a few weeks in the summer of 2003 while my magneto was being rewound by Dave Lindsley in Heywood, Lancs. I should have known it was failing, but I was in denial until both cylinders just cut one day. Now it's amazing - starts 1st kick, and idles OK at traffic lights! I don't like riding on fast highways with a top speed of 65 mph being as fast as I like to go, with no reserve of power. But Vermont back roads are probably much like UK in the 1950's, so it just feels right those days. I love to ride the Mark, when it's running well, but I just seem to spend more time working on it than riding, and I never have 100% confidence I'm going to get home again. Upgrades like modern oil seals, etc. help.  The original design had optional air filters, and a simple gauze strainer in the sump for the oil. I suppose that's asking for trouble. I rebuilt the crankshaft a few years ago, after the infamous blocked crankshaft oil channels disaster. I built a jig to press the thing apart, and together, and got some parts (including rollers) from John Ramsey in Preston, UK.
Note that this bike is not quite original - especially the dual seat, exhaust system is Mark V not Mark III
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Figure 2: Left view 2003

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Figure 3:  Right view 2003

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Figure 4:  Joy ride

VERMONT SCENES

The landscapes and structures of Vermont serve as a perfect complement to the beauty and elegance of the Douglas Mark III.  Covered bridges in Vermont are often re-inforced with some steel components these days.  The roof is to keep snow off in the winter, and to protect the structure from the elements.
 
 
 

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Figure 5: Fall 2003 - Near Underhill, Vermont
 
 
 
 

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Figure 6:  By Sequin Covered bridge, near Ferrisberg, Vermont . A Burr arch design, spanning 21 m (71 feet) over the Lewis Creek.  Built in 1849

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Figure 7: By Holmes Creek Covered bridge, Charlotte Vermont  A tied arch design, spanning 12 m (40 feet) over the Holmes Creek.  Built in 1898

LONDON DOUGLAS MOTOR CYCLE CLUB (LDMCC)

Click here to see their web site:   London Douglas Motorcycle Club

Serves owners of the Marque with a bi-monthly magazine, pre-war and post-war spares sections, regalia, annual meeting, etc.
 

SECTIONAL VIEW OF A MARK - as published in Motor Cycle Magazine

  What a beautiful design.  Notable features include:
- the famous horizontal opposed twin cylinder engine (Introduced by Douglas in 1907 and subsequently favoured by BMW),  You'll never get cold feet (but your shoes come out smelling of hot oil and fuel leaks).
- the 'Radiodraulic'  front forks with a complex linkage system acting on the coil springs housed inside the down tubes,
- the torsion bar rear suspension, with the bars housed inside the lower tubes of the frame.
- Lucas 'Magdyno' electrical system, with separate magneto for ignition and 6V dynamo for the lights and horn.  Yes, Lucas - 'The Prince of Darkness'.
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Figure 8:

TECHNICAL INFORMATION - SUSPENSION


 
The front suspension uses coil springs, acted on by a complex lever system from leading links. An oil damping system is included. The rear suspension uses a mechanical linkage system to torsion bars housed in the lower frame members. The complexity (and presumed manufacturing cost) of both front and rear suspension may have been part of the reason why the Mark series was later discontinued in favour of the Dragonfly.  But the ride is superb!
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Figure 9:  Front Suspension (From Douglas Maintenance Manual 1948-1954)

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Figure 10: Rear Suspension (From Douglas Maintenance Manual 1948-1954)

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Web Page Author:
Ian Stokes

Last Modified: 6th August 2010