Does getting an aftermarket pipe affect your gas mileage, or not really?

 

Are you talking for a 400 or 500.
2 stroke or 4 stroke

I speak from experience on My 2000 400 that my fuel mileage went way down with just a pipe and clutch kit, Now My 99 with the 440 big bore and 42mm carb is absolutely terrible.
In stock form they are much better

As for the 500 I don't think they are as bad, More gas is used just because you are in to the throttle more.

 

Everything’s a compromise. You want to go faster you fit a better pipe; you fit a better pipe the engine “breaths better, when the engine breaths better it will burn more fuel. In a word “yes”….[img]i/expressions/face-icon-small-smile.gif[/img]

 

Think of ur motor as a pump, faster in faster out, so yes.