looking for some insight; I just picked up a 2009 VFR800, it has a two brothers exhaust; is the exhaust system four into two or for into one? one pipe is idle while the other handles the load. thanks Don.
Welcome aboard, Don! First things first ... pictures or it doesn't exist. The stock exhaust is 4 into 2. TB exhaust I believe is 4 into 1 with the second can being a dummy. Some of the dummy cans came as kits as an under seat stash. What model of TB exhaust does it have?
The factory exhaust is 4-2-1-2 The Two Brothers is 4-2-1 The reason the factory exhaust is split back out into 2 mufflers is because the factory mufflers are restrictive in order to meet noise regulations. After market mufflers are straight through with basically zero restriction (unless you are running a sound reducing silencer), so there is no benefit in splitting back out into 2 mufflers. When using one straight through muffler, you can design a straighter and higher flowing exhaust flow path that is actually lighter as well. The only benefit to running dual straight through mufflers is purely aesthetic, unless you are running silencers inserts, which is honestly counter-intuitive.
