You should likely leave it as is.
The balance pots/transfer tubes are there to enable one pipe to assist another in scavenging and extracting from the cylinder using harmonics from the other pipe. Your pipe was tuned to your duplex design. Also, that pipe was meant for a fully built 145+hp XRO Factory Superbike....
Some on, we did the srad Mikuni carb choke the other day, and it misconceptions, today its the infamous "backpressure". Tell me about it, what is it really?
The op says his D&D had no backpressure because it was "straight through"....is that true?
I used to know Dave Rash of D&D and watched him build pipes for me for new models....he never worried about "back pressure".....so tell me about back pressure.
""Positive and negative pressure waves wash back and forth through the length of the pipe and pipe and can design affects the timing of said waves and their arrival back at the motor. Good pipe design, among many other things, takes into consideration the design of these so as to ensure that negative pressure waves do not arrive back at the exhaust valves at periods of valve overlap and therefore bring with it burnt exhaust into the combustion chamber, and and in some cases into the intake track. Then, the next firing cycle attempts to ignite a mixture of of new fue/air and burnt byproducts.*""
I know back pressure has something to do with resistance of exhaust gasses flowing through the system. You can lose power if your engine is not properly tuned for an aftermarket exhaust system. My guess is that the scavenging effect is too great on the cylinder and the engine runs a leaner mixture.
APOK........ITS NOT FAIR TO COPY AND PASTE MY OWN POSTS, GOOD ANSWER AND RESEARCH HOWEVER,....
The rest of the answer is that it is not relevant if is straight through or not, how big the bore is etc, its not back pressure......there is no real back pressure. What there is, is how effectively you can evacuate a cylinder, and how effectively you can tune the harmonics of the pipe to assist in both this and returning negtive pressure waves during periods of valve overlap (using combinations of collectors,total lengths,lengths to collectors,lengths of silencers,diameters,stepped diameters, etc.).
Now, the midpipe exup type valve is a different discussion entirely.
1996 GSXR 750 EX AMA, Carillo, Yoshimura, Kit airbox, Keihin FCR39, Fox, Brembo, Hindle, total loss and starter less ignition, Graves, Vortex
In 2t the power pulses help scavenge the barrel. I thought back pressure was only a problem in turbo cars. Too much back pressure can cause the impellor to stall. In n/a back pressure isn't as critical