Hello all readers of this forum!
Since it's been 15 years from my first post, I would like to make an update on my Douglas Mark 5.
A VW Beetle oil pump was installed already in 1972 (please see photo). The oil pressure was plain zero with the original pump. The original pump was used only as transmission shaft for the VW pump. External piping and blocking the oil passage between the crankcase halves was necessary.
In the year 2005, the cylinders were rebored and Honda CB 750 pistons installed. Rocker arm ball sockets from Mercedes Benz were installed to avoid contact between spherical valve adjusting screw and flat valve tip (photo).
Back in 1969, the bike had come with the left hand toolbox only. The footpeg bracket in the toolbox was broken as well. In the year 2005, a right hand toolbox could well have been obtained from the web. Anyway, I deciced to go the hard way and fabricated the right hand toolbox from sheet metal as mirror image to the left one (please see photo).
Several fractures in the frame were detected in the year 2015. The torsion bar tubes had broken already in the 1970's, and I had made a bodge repair back then. The bike was basically held in one piece by the engine and gearbox only. The frame was completely torn down to separate pieces. Solid steel pins were hand- ground and filed to fit snugly inside the tubing. Loctite and transverse screws were used to make a solid joint (please see photos). No soldering was used.
Simultaneously, when the bike was taken to pieces anyway, I managed to make one good gearbox using parts from two gearboxes in bad condition. The felt seal of the output shaft was replaced using a sealed ball bearing.
I hope that this story of my bike will be interesting and useful to other post-war Douglas mechanics.
Best regards
Erkki
Vaasa, Finland
VW Beetle oil pump installation
Smiths chronometer and Yazaki oil pressure gauge
MB rocker arm ball socket
Frame repair rear
Toolbox made of sheet metal
Images converted to linked files - Dave, 29Sep2021
