There's been a few comments made in another thread as to whether a 2 stroke engine run very rich actually "skips a beat" or if it's just the exhaust sound. I must admit I'd always thought it was most likely because the very rich mixture burned more slowly and was still burning when the exhaust port opened giving more of a "woosh" than a "bang". But I couldn't understand why there was such an immediate transition between the two sounds. Some time ago I came across a couple of graphs that showed exactly what was happening and with the permission of Brett Buck (who did all the work) I've included them in the web page I do for my club at http://www.holdfastmac.com.au/424stroking.html

The graph for torque shows quite clearly that they DO "skip a beat". The second graph shows the affect the varying torque has on prop speed which is rather interesting in itself

good info. I'm sure there will still be non-believers that stubbornly refuse to accept that a 2 stroke engine can fire every other stroke when run very rich. I wish someone could post the Dave Gierke article and graph he did in the last few years on this very topic. I think he wrote the exact reason for the 4 stroking wasn't fully understood and/or agreed upon by engine gurus and engineers. (I think)