Let’s consider yet another figure of merit in engine performance: brake mean effective pressure (BMEP), which is stroke-averaged net combustion pressure (net means with friction and pumping loss subtracted). It is a measure of how well an engine fills its cylinder(s) with fresh mixture, and how efficiently it burns that charge. In the case of Suzuki’s 125cc twin, this was 112 psi, and for Yamaha’s RD56 of 1964–’65, 130 psi. Compare this with good four-stroke peak BMEP numbers, which for years have been (and today remain) in the range of 200 psi. Bear in mind that a two-stroke produces this effect every time a piston comes to TDC, while in a four-stroke it is only every other time.