Custom exhaust

[ManagerMike]

As a thought provoker I will share my custom exhaust "invention". When I first accuired the bike some PO had hacked in some cheap beaten and rusted mufflers onto the oe collecters. Perusing the Napa catalog I ran across these 24" chrome tail pipes

Not wanting fully open "drag pipes" exhaust, I created baffles out of two 14" long by 1-1/4" steel tubes that I cross drilled with 3/8" holes (12 holes through both walls of the tube) and welded one end closed then welded them into the collecters. The pipes slipped snugly over the chrome shield and I welded them in place on the back and bottom sides where it doesn't show and "caulked" the rest with two part epoxy to seal any leaks. I did not have a camera at the time, so I made a diagram for clarification.

Final result:

Sounds awesome and retains some unknown level of backpressure we all know these bikes want.

[WSL91]

looks great, now if we only knew what the back pressure measurement needed was and how to test for it.

[lee_dutcher]

Should do a video clip ......would like to hear it

[CaptonZap]

looks great, now if we only knew what the back pressure measurement needed was and how to test for it.

Well, if someone in the Denver area had a bike dyno with a brake setup, as apposed to the inertial kind, my pipes have some cute plugged ports at the bottom of the head pipes, and I can come up with a gauge setup. CZ

[Rasputin]

I know a few heavy duty diesel mechanics that have back pressure guages. Sometimes oilfield equipment will be run with straight pipes as they are out in the middle of nowhere (at least around here). They simply hook them into the plugs and measure the back pressure. When one is dealing with 3-4 thousand horsepower engines any decrease in performance is critical so they need to know. The guages are capable of very fine measurements so they should work anywhere. I can possibly find out the back pressure on a stock system but unfortunetly all of my runners have headers, so I would have to do some swapping. That would mean re-tuning and in most cases re-jetting so I do not think that will happen before winter. I just had to bring it up in case anyone had the capabilities or equip to do a test.