Modifying exhaust header for 2 into 1

[fredskidoo]

Looking for some discussion about modifying stock exhaust header for 2 into 1.

1. Would simply cutting off one side (sealing the hole, of course) suffice?

2. How would the back pressure be effected? More or less muffler baffle?

3. Would changes to the carburetor be necessary? If so, what?

4. Any other considerations? Valves, timing, etc?

Easy - E

[jpitz31]

The simple answer is that changing to a 2 - 1system is suppose to increase your torque. But the long answer is that there are a lot of variables to this answer.

Exhaust pipe diameter, exhaust pipe length all can induce changes to back pressure, and the scavenge effects of exhaust flow.

Just cutting off a pipe and running one exhaust pipe is not the answer.

AFR will be effected by change in back pressure and timing may be affected as well.

There are vendors who do offer a 2 into 1 system that changes back pressure. On the FI Ducati's this requires a chip change to compensate for the change in back pressure and exhaust flow which affects AFR.

higgy would know more about this, and could provide more particulars.

To do it right re-jetting is in order and maybe some dyno time to check for possible low, mid and high range changes in performance.

Just my two cents.

Cheers

Joe

[paso750]

maybe of interest (nothing new, all available in my downloads thread)
http://www.box.net/shared/yrb6c0887z/1/4238463/36248809
http://www.box.net/public/4rd2q3kljs

[jcslocum]

Pics of my 2:1 system







The 2 pipes need to be the same length for the flow and scavenging effect to be right and balanced.

[Tamburinifan]

Real nice, jon!