By rotaryvalveman at 2010-07-03
this is a computer generated picture of the actual head I had the best results with. it was on a 450cc single cylinder unit and the picture is the head on it's side with the exhaust port visable and the exhaust side of the combustion chamber to the left. The drive mechanism is not seen but within the case is the secondry reduction of the 2:1 drive to give the final 4:1 we ran with.
this model was put into 3D CAD after we made it and it has to be said that we did it the other way around. we actually made this freehand on the fly and drew it afterwards with a few hand drawn scetches along the way and a little geomectric checks in 2D CAD as we went to get timmings somewhere near. Hey, time was short. we finished cutting metal on a Saturday morning and had it running by lunch. That was where we stopped almost a decade ago and never optomised it but now we will.
That looks very similar to mine. Big coincidence though, mine is a little different. I had some issues with the head bolts so I sorta stopped there. I will post a few pictures.