I have a 2.5" exhaust with only one muffler at the back, which is loud as all urine and Im wanting to quieten it down. Today I went to the muffler shop and the guy there reckons 2.5" is too big for a 4AG because it doesnt have enough back pressure and 2.25" is the maximum size he'd go.
I know that small engines need back pressure but my cams apparently have the inlet and outlet valves open at the same time and I don't know weather this is why there is such a large exhaust.
I also have an almost complete 2" system I could put on.
Does anyone know anything to help me out?
