Lohmann
18cc "Diesel" bicycle clip-on engine.
Click for bigger pictures.
 
In the years just after world war two many ingenious bicycle engines were designed and made all over Europe, to satisfy the giant demand for cheap motorized transport, but this one is more ingenious than the rest. 

Made in Hamburg Germany from 1949-1954 to run on just about any fuel from lamp oil to petrol/gasoline/Benzin, with variable compression ratio to adjust to different types of fuel. There is no ignition system as such. Like Diesel engines it works by compressing the fuel/air mixture hard enough to get it so hot that it self-ignites. The designer Hermann Teegen decided that 18cc was enough to keep up with the less sophisticated competition!

So not only do you have to pedal to start it, you also have to juggle two throttle twist grips; one for the "carb" (which isn't actually a carb as we know them, of course) and one for the "false roof" of the combustion chamber that screws up and down to adjust compression. By all accounts it is not easy to do, but it can be done. Scroll down for pictures of some of the documentation - including the factory instruction book - that comes with the engine.

This is your chance to get your very own example of this mythical engine, clip it onto a suitable old bicycle and attempt the real achievement of mastering the Lohmann :-)

There were two different mufflers. This one is (I think) the 1952 model, and you can see the earlier one - also included - below.

There has been some repair work done, but it is done neatly; someone has spent a lot of time on this engine. Roller ->

The two holes are for the variable compression cables; see documentation below. "Carb" by Meco, Bielefeld.

Another view of the Meco fuel mixing apparatus, air cleaner, bicycle frame mounting lug, and a few other details.

Mounting brackets for the bicycle frame (see docs below), note shims on the pivot bolt for the main bracket for slop-free mounting. Designed and made by Germans :-)

On-Off lever with linkage, main bracket pivot bolt, early model muffler; three hands needed to both photograph it and show that the spring is pushed open from exhaust pressure, and cosing (like here) when the engine stops.

Magura. One of the two double cable throttle (compression adjustment, in this case) twist grips included.
I bought it many years ago with the aim of clipping it onto a period bicycle, but never actually did, or even tried to start it. The former owner had rebuilt a few of them before, and I bought his last one for quite a bit of money; it is a very cool engine! I am unlikely to get around to doing anything with it before I am too old to pedal, so time to find it a new home.

There is most of the mounting brackets and such with it. You may have to make some small mounting parts and find a few standard bolts etc, but that part of it shouldn't be too difficult. The papers have good illustrations and fitting instructions. Also two exhaust mufflers of different designs; see pics and compare to papers below. There are also two (two-way) throttle grips of the period, but I can't say if they were the actual model supplied by Lohmann. You are perhaps unlikely to run into any Lohmann experts to tell you they are wrong though!

It turns smoothly and has compression, and even a new roller to drive the rear wheel. Good signs, but I only have the rebuilder's word for his work. I have since lost contact with him (if he is even around anymore), but he was well-regarded in local old-bike circles, and the engine looks and feels pretty good.

There is extensive documentation with it. From the factory instruction book in English, over a useful fuel mixture chart and parts book copies in German to several articles and other papers in German, Dutch, Swedish and Danish. Here are some of the papers.


Fuel information: setting the carb etc
More carb info ->

Documentation. The long paper is a Danish translation of the instruction book ->