Curious re my 2003 RoadKing - does the rear cylinder have less back pressure because it has two exhaust pipe outlets vs. the single front? Did the split double rear pipe have an engineering function or just for the look of right and left exhaust? This is my first post on this forum so please excuse me if this has been asked before or is a dumb question.

 

Really the OEM Header system is a good system and has worked well for HD for many years...
2-into-1 will give you the performance gains
Where as 2-into-2 looks better (for the most part) on baggers

 

The crossover is meant to equalize exhaust flow between the cylinders.

 

I always figured it was a 1-1/2 to one I believe that crossover helps on scavenging, back pressure and balances the bike (as for looks). They could have easily made it a 2 into 1 but the current setup looks better on a stock bagger in my opinion.

 

Good question. I figure 20% of the exhaust from the rear cyclinder exits the left pipe. I did this test with a velometer placed at the muffler outlet at 1800 RPM. Certainly not scientific, but satisfied my curiosity. I'm going through this right now with my softail that I recently bought a stock springer classic exhaust for which has tha same setup for the left side pipe. The branch comes out at a wierd angle and is only 1" diameter. I'm cutting it off and welding it shut, puting a SE slip on on the end and gonna try it. I just like the retro 2 into 1 look is all. Just fartin around with it.

You'll get lots of opinions, but most performance guys will tell you that stock head pipes with Bub slip ons get you the best bang for the buck. That true duals will take away some of your lower RPM torque.

 

Thanks guys - got my answers - I'm very happy with stock - was just curious. My stock 40 Knucklehead is 2:1 and that's just fine as well.