Pistons orchestrate the suck, squeeze bang, blow mantra we are all familiar with. More specifically, the piston transfers the energy from the expanding gasses of combustion to the crankshaft, via the connecting rod. To do this efficiently it must optimise the pressure by sealing the combustion chamber – with assistance from the piston rings – against gas leakage into the crankcase and prevent lubricating oil getting into the combustion chamber. On top of that it must absorb heat from the combustion process and dissipate it into the cylinder wall.
With combustion temperatures in excess of 2000°C the top of the piston will typically run at around 300°C. The piston may be subjected to pressures as high as 3000 pounds per square inch and huge forces of inertia caused by the extremely rapid acceleration (positive and negative). The piston stops at the top and bottom of each stroke to reverse direction and reaches peak velocities of around 40 metres per second in between. In 10,000 miles a typical superbike’s engine’s pistons will have travelled around 14,000 miles and reversed direction one hundred and fifty million times.
The very embodiment of internal combustion and the hardest working component in your engine
He’s had 30 years of experience building, modifying and repairing bikes from supermonos to CBX1000 café racers.
In 10,000 miles your piston will have been up and down 150,000,000 times