Rod Gibson gets to grips with the science of camshaft design, and enters a world full of ramps, overlap, lift and durations. But will it make the bike go faster?
We tend to take camshafts for granted, or at least I did until quite recently. Coaxing a little more power out of our project Katana meant that, like it or not, I had to get to grips with a little cam technology. But before we plunge too deeply into the strange world of ramps, overlap and durations, here’s a quick trip around the trusty camshaft and its place in the world of internal combustion.
Any engine has to have some provision to get gas in and out of its cylinders. In a conventional four-stroke engine the job of the inlet valve is to open to allow fresh charge into each cylinder, then close to allow it to be compressed and ignited. After combustion, the exhaust valve opens to let the spent gasses out, then closes to allow the whole cycle to repeat.