Cat replacement pipe for my Hachi (in the UK) - Weird

[Ivan141]

Hmm..interesting exhaust indeed. Many dutch guys are a bit familiar with expansion exhausts since lots of us used to tune mopeds before we were old enough to drive cars. On a two-stroke the exhaust shape makes a HUGE difference in performance since getting the exhaust pulses just right ensures that exhaust gasses get out as fast as possible and incoming fuel mixture (which overlaps exhaust gas escaping) is optimised by the backpressure wave.
I havent thought it through for a four stroke, but it would only help to get the exhaust gasses out of the head faster. If that helps performance a lot, then I would like one of those masterpieces on my 4age.