This video of a BMW S1000RR125cc engine revving to 14,200rpm with the valves operating has just surfaced after being released by BMW USA.
The video shows the valves, rocker arms and springs operating from idle through to the maximum revs of the 999cc inline four-cylinder engine.
We think the cylinder has been cut away so we can see inside and it’s running open to the air judging by the amount of oil spraying out.
Watch out for the oil vapour produced as the revs rise and the valve springs rotating around the valve stem.
Also note how the camshafts appear to run backwards as the revs rise.