Ok... well... I'm just a system guy, and not an expert by any means in Diesel Truckin.
BUT, I do know something about Diesel that not many other people know.

There is a tree in the Amazon region of Brazil, known as the Copa Iba tree. You can put a "bung" hole in this tree and tap it just like you do with Maple trees to get maple syrup... except the sap of this tree is pure Diesel fuel!!!

It is TRUE! You can tap the tree twice a year for about 5 gallons each time. There is NO refining necessary. Just put it in your tank and go. Mother nature takes the carbon monoxide out of the air and refines it it the tree itself.

While Amazon Indian tribes have known of the tree for centuries, it was not recognized by researchers until University of California chemist Melvin Calvin saw it for himself. He actually got awarded a Nobel Prize for his "discovery".

Over 20% of the diesel fuel consumed in Brazil now comes from the Copa Iba tree. Now that IS BioDiesel.

Stick that into your tank and burn it!!!

Diesel Bicycle Engine

The 18cc engine is of German manufacture and is designed to be clipped onto a bicycle. Its bore was 28mm and stroke 30mm. Made in the austerity era after WW2 it sold for the sum of £25.45 and was ideal if you needed to travel about cheaply giving its owner a reputed 300mpg!. Different sorces say the engine was produced in either 1949, 1951 or 1952. Fitted below the crank this engine drove the rear wheel by means of a roller. The interesting thing about this engine was that the compression was variable due to the fact that the 'Head' was movable by twist grip throttles. One presumes it was adjusted to what fuel was being used with the ignition taking place under compression. Apparently the engine came with a booklet carb jettings for various fuels. It could be run on either gasoline, diesel, kerosene or lamp oil. For the record compression ratio limots were between 8:1 and 125:1. The makers recommended 30:1 for starting the unit and 17:1 to run it. Top speed was said to be 16mph with the 2 stroke engine running at 6000rpm (0.8hp). It was said to be able to rev to 9000rpm (23mph).