build two but one bigger than the other. Cut the bigger one in half and slide it over the smaller one. You would have to weld spacers in between the two. But idk how they are put together I have never cut a dry pipe in half. Or just make it a wet pipe like b pipe but with the better PF design. Just looking at all the retarded angle loopdeloops the exhaust has to do just shows how inefficient they are. Same with the carbs, they suck from the top and make a right angle into the motor. But obviously thats how it has to be to fit in the hull and not suck water.
My guess the b pipe lacks easy flow but has a longer expansion chamber starting from the manifold going all the way to the side of the gas tank thus making the power curve lower. But lacking the flow to support higher reving HP.
PF pipe has a way better design even though I think the cast collector could have been built with less right angles in it. But the better flowing less sharp curves make more power. Also the shorter expansion chamber. Like I have read a b limited chamber makes more low end than the shorter mod chamber. Im guessing thats why your supposed to put the mod chamber on a bigger motor, because the bigger motor makes more low end anyways.
This brings me to the stock yamaha bread box. WTF is that. why does it even allow the engine to run?
Hopefully I dont get flamed for this post but these are just observations. I have never even seen these pipes in person (untill the one I bought shows up). Just throwing out ideas to try and get educated on the black art of 2 stoke pipes.