Running 1/2" pipe is to small, there is increased resistance with
increased length of exuast, figure 4-7 elbows to pipe it through that
will increase resistance, back pressure and increased head temps come
into play. Increase back pressure and lower hp. The honda is already
choked down so much you can hardly hear it run, lower hp on a 2000w
unit, its already under powered for most users. Just hook up a pipe you
say, what about water collecting at the low point and choking the motor
off, or water dripping back into the cilinder, not good, you can ruin
your motor. There will be water as the vertical rise cools. Just a few
things to consider and why 1/2" won`t work.