Someone then experimented on a four-cylinder with the cylinders arranged in line. This posed a problem as the direction of rotation of the crankshaft had to be turned 90 degree so as to drive the rear wheel with a belt. Then some tried with four placed across the frame, this way they would not have the 90-degree problem. The experiment went on from a single cylinder right up to seven cylinders. Though single were simple but wait, should the engine be right up with the cylinder head uppermost or should it be horizontal with the head forward or should it be just facing forward 45 degree? Then they went on with the twins. The natural thought was to put the twin cylinder alongside each other after all they are twins aren’t they. British twins had the two pistons going up and down differently or the cranks were set 180 apart. The Japanese then came and saw that the twins were acting differently that’s why it leaked oil so they set the twins to run together, 360 degree apart. Twins should act similar thus cylinders were made to go up and down together and hey presto! No oil leak! It was the natural way to go then until someone the famous Siamese twins appeared in headlines all over the world. Engine designers got inspired and decided to split the twins. From the parallel twin the V-twins and flat twins were born. Flat twins were simple so you thought. How flat can one get. Yes flat but should it be left and right or front and back? Front and back? Yes the fore and aft cylinder arrangement. Though it increased the overall length of the motorcycle it did get into production. Coventry Eagle had a 1000cc with this cylinder setup. For a flat twin, should the cylinders be firing in different combustion chamber or should it be a common chamber. Firing into one common combustion chamber never made it big. Whilst you save on the number of cylinder heads the machine would need to have 2 crankshafts, two sumps and so on. That is 180-degree flat, no more no less but a V twin. How wide must the V be 60, 70, 80, 90? This argument goes on till today.

That’s the story of the twins. Then there are also triplets. Should the triplets be set together? How else can you arrange 3 cylinders? How about a V? Yes a V triplet. The middle one cylinder facing forward and the two outside cylinders stand upright. Who would want to build one like this you say. But that’s not a V, a W maybe. Whatever DKW produced a very successful racer in this configuration once and were copied several times by many racers since.

Lets get to four then, you have an inline parallel four, an across the frame parallel four, a V four and a Flat four and a square four. A square four would be like two vertical twins set side by side, thus that means having 2 separate crankshafts.

Through the colorful path of motorcycling history, designers went up from 1 cylinder to 5 cylinders then 6 parallel 6 Vs then 7. Seven? Yes a manufacturer once produced a bike with 7 rotary cylinders. No, not rotary of the Wankel kind like Hercules or Mazda but seven cylinders arranged in a circle like early airplane engines.

Today you get customizers squeezing V8 and V10 into bike frames. But then these are one offs and I shall not look into them.

©2009 dr-moto.com