Join Date: Oct 2017
Location: Near Atlanta, GA
Does Putting a High Flow Head Pipe on the 107 M8 "Transform" The Motor?
I've put the Fullsac headpipes and baffles on all of our Harley's and never been disappointed. Amazing sound and great performance.
However, I've held off on putting the headpipe on the 2017 FLTRU for a couple reasons. One is the MOCO's crackdown on EPA violations and another is not wanting this bike to be "loud". But, to be fair, the Fullsac headpipes and baffles with sound batting have always had a nice note without being too loud on the Twin Cams.
So, I've tried to 'accept' the M8's unique sounds for the past year and have limited my mods to Reinhart cans with Fullsac sound insulation, a Ventilator intake and a Dyno tune that has the motor making 81 hp and 105 ft lb torque.
As you'd expect, it doesn't have the get-up-and-go of my 2013 FLHRSE5's 110" motor with the Fullsac headpipe, etc. at 96 hp and 112 ft lb torque, and forget about keeping up with the Honda F6B at 112 hp and 122 ft lb torque.
But, what's bothersome is what sounds like a ton of back pressure at the collector pipe & cat on WOT and the very uneven exhaust flow out the two tail pipes, where the left pipe pretty much functions as a by-pass under harder power output.
Definitely conflicted, but starting to lean towards doing the head pipe and just "talking out loud" to see if I can push myself over the edge to order the pipe at this point.
So, to those who have changed out the head pipe for an aftermarket pipe (not just gutting the cat), much difference did it make in terms of power and the sound of the motor / exhaust flow?