in 530088 20060507 183910 "Sylvain VAN DER WALDE" wrote:

However, tuning the
exhaust system gives lesser results in comparison with the effects of
tuning the input system (by quite a lot)

I believe that 2 stroke (racing?) engines were greatly improved (over a
narrow revolutions band) by tuning the exhaust.

Not just racing engines - in the 1950s I had a 125cc BSA Bantam.
One day the nut holding the exhaust end-cap on came off and the entire
contents of the exhaust were shot out backwards. This affected the engine
power output to the extent that I could barely ride back to pick up the pieces.