OK Greg,
Thanks for the reply, I understand that all that air must go somewhere, but isn't it supposed to be all displaced out the exhaust? If the piston is going up, the valves are closed, the air/fuel mix is compressed, and ignited by the spark, which pushes the piston down, right so far? 8)
Then, the piston goes back up, with the exhaust valve open and the combustion residues are pushed out thru the exhaust, right? 8)
With the inlet valve open, the piston goes down and sucks air/fuel mix into the chamber, and the cycle begins again... 8)
Now, where is that air you talk about coming from? My mechanic tried to explain it to me, but gave up after the fifth try
I'll keep you posted on my discoveries...
RW