I put this guide together to explain how to measure the cc of combustion chambers.

Sutff you need:

• Liquid Paraffin - from a pharmacy - after you get it, put it in the fridge - makes working with it easier.
• A small syringe - from a pharmacy.
• A flat piece of plastic or glass with a (preferably small) hole in - either home made or from the glaziers.
• Spirit level.
• A spark plug.
• Some grease.

First you need to get your cylinder head on a flat and level surface.

Next grease around the outside of the chamber, and the valve seats. Screw the spark plug in to the chamber you are going to measure - finger tight will do.

Place your flat piece of glass or plastic on top - making sure its nicely sealed around the edges - we don't want leaks. Here I've used a spacer CD that you get when you buy packets of CD-Rs - it's not ideal but it works.

Next fill your syringe up with the liquid paraffin - making sure you don't have any air bubbles - and that it's accurately up to the 5ml mark.

"Inject" contents of the syringe in to the hole. Repeat this until...

...you can see an air bubble - you may need to gently tilt the head until the bubble moves to where the hole is.

Carefully fill the final amount and note down how much you added. Add it all up - and that's what your cc is.

This head, a Triumph Spitfire 1300 head that has been slightly skimmed, has combustion chambers of approx 32.75cc.

The technique is exactly the same for dished pistons. This Triumph Spitfire 1500 US spec low compression +030 piston has 6.25cc of volume.