Stock Head Pipe Mod

Discussion in 'Engine, Fuel and Exhaust' started by propflux01, Feb 27, 2010.

  1. propflux01

    propflux01 Active Member

    Will this work?
    I have an 03' Ultra and it had this horrible looking true dual setup on it. So I removed it, and installed the stock HD headpipe assy back on it. When I started it, i noticed most of the exhaust coming out the right pipe. On the rear cylinder, the pipe branches out two ways, and what I would like to do is block off the side that goes to the right, therefore letting the rear cylinder go the the left side pipe, and the front cylinder going out the right, sort of like a true dual, but with stock look. The stock pipes are the same diameter as my duals. I would like to install some kind of baffle or plug in it so it directs that rear cylinder to the left side pipe. Has anyone done anything like this? If so, what was used to do it? My reasons for doing this are twofold, one, is cost. Two, I kinda like the way the stock pipes look, but want performance of duals.
  2. glider

    glider Veteran Member

    The engine runs it's best plumbed the way it is from the factory. It provides scavenging for the system between the cylinders. Some bikes also have different mufflers for this too, restricting the left side to promote the right side flow with both cylinders. I wouldn't try what you are thinking of doing but I would replace with a system that is meant to flow both cylinders like you want to do.

    PS. The "performance" isn't with true duals either.
  3. Breeze3at

    Breeze3at Well-Known Member

    I agree with Gliders recommendation. But "if you must", you can go to the auto parts store and get a freeze/casting/expansion plug to block off the right side. When you decide you want it back like it was, drill a hole in the plug, insert a sheet metal screw and pull it out.
  4. propflux01

    propflux01 Active Member

    Ok then. The reason I had this idea was that there was so much flow coming out of the right side, and nothing but cold air puffing in and out of the left. Seemed the left side was useless. Where it splits at the 'Y' on the rear cylinder, is where I had wanted to plug or divert flow to that side (with a small hole drilled into the plug for some reversion effect). With stock setup, (pipes are V&H Slip ons) the bike reacted like there was more cyl pressure going out that right side than the pipe could handle. Seemed like it couldn't get enough exhaust out. Guess I will figure something else
  5. Chopper

    Chopper Senior Member

    Had friends that ran Rinehart's slip-on's with the black tips, after a while the right tip would turn a golden brown from the heat so they would swap sides and then they would match after a while. The cross over system to equalize the exhaust pressures is important, it allows the cylinder exhaust pressure to equalize itself by using both pipes together as one, if you have a dyna or softail the pipes are short enough not to be a big problem as true duals, but on a touring bikes with the long exhaust system when you go true duals one pipe is longer then the other pipe causing different back pressures to each cylinder and when you put the bike on a dyno and monitor it you can see the change in volumetric efficiency between front & rear cylinders, that's where fuel injection comes in real handy because you can build one fuel map for the front cylinder and a totally different map for the rear cylinder, you can't do that with a carburetor, a carburetor is a compromise, that were Bassani true duals are good to use because they lengthen the rear pipe to make the back pressure more equal to both cylinders and that makes the true duals more forgiving to use on carbureted bikes. I don't have any education past ninth grade so you can ball this whole spiel up and bury it in 55-gallon drum, but it's just my opinion on what I've seen in my own personal experience with bikes.