FAQ: what does cc mean?

If you are around motorcycles, or indeed internal combustion engines powering anything, you are going to hear the term ‘cc’ a lot. For our purposes, it’s an integral part of motorcycle designation.

But, don’t worry. It can look and sound dreadfully complex, and the truth is, if you delve deep into the mathematics it can be very puzzling indeed. But, for everyday purposes, the whole deal is pretty straight forward. Let’s have a go at demystifying all this.

An engine’s size is otherwise referred to as ‘engine capacity’ or ‘engine displacement’. The number is expressed in cubic centimetres That’s the elusive ‘cc’ initials we are talking about.
Put as simply as possible, it’s a measurement of how large a space in which the engine’s pistons operate.

The higher the number the more air and fuel are passing through the engine’s combustion chamber – that’s where the explosion of fuel and air takes place to move the pistons up and down to create power. It’s not always the case, but in a general sense the higher this number is, the more power you can expect the engine to produce.

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Again, there are notable exceptions here. Let’s not bog down there though.

So, we’ve established that the term ‘cc’ represents the displacement of the engine measured in cubic centimetres. To help with understanding this a little further, one ‘cc’ is one thousandth of a litre. Just like when measuring liquid. Therefore, a bike that has a one-litre engine will have a 1000cc capacity.

Remember, this is the volume of air (or the air/fuel mixture) in each cylinder multiplied by the number of cylinders. Again, revising, this is best referred to as ‘displacement’. It’s used to refer to engine size, but really, it’s just that volume figure we spoke about. You still with us here?

For the more advanced among us, or those a little ahead of the game, the displacement is a calculation of the bore and the stroke. The bore is the diameter of the area swept by the piston and the stroke is the movement from top dead centre to bottom dead centre. To calculate it the equation is: Displacement = stroke x pi x [(bore/2)(bore/2)] x [number of cylinders] .

Okay. That’s the propeller head stuff. In short, the term ‘cc’ refers to the size of an engine in terms of the number of cubic centimetres that the piston displaces in regard to the air and fuel mixture inside the business end of an engine. There you go. Now you can amaze your mates. Go to it.