I found such a bike for sale on ebay and judging from the pictures, the exhaust functions the same as what the touring bikes used up through '08. The rear O2 sensor in them was on the "crossover" to the right, indicating that primary flow is in that direction. The (closed-loop-version) left muffler was just a big empty chamber with a short closed-off-on-the-inside-end outlet pipe containing a dozen pea-sized holes. It obviously didn't flow as much as the right-side muffler once much above idle, and it evidently succeeded in containing and keeping reverse-flow from reaching the O2 sensor. It's been fairly common knowledge that a more-restrictive left-side muffler works best on those hybrid 2:1/2:2 systems when going closed-loop.
The same combination of mufflers is currently used on the newer touring system but I highly doubt any fresh air which might flow left-to-right would ever find its way to the rear O2 sensor location now.
The moco's story about wanting to remove an underseat heat source for the tourers by going to the 2-1-2 in '09 might have bearing, but I'd wager it was more to get clean O2 sampling on the rear cylinder instead. A quick look through the '09s and '10s at HD's website just now leads me to believe they've gotten totally away from the old "crossover" setup (maybe since now all the bikes are closed-loop?).
I know my '07 tourer rumbled on decel quite a bit more than does my '09 with exactly the same "stage 1" equipment in service. I rather liked it, but don't exactly miss it either. I'm confident that my closed-loop tune is better as a result.
The same combination of mufflers is currently used on the newer touring system but I highly doubt any fresh air which might flow left-to-right would ever find its way to the rear O2 sensor location now.
The moco's story about wanting to remove an underseat heat source for the tourers by going to the 2-1-2 in '09 might have bearing, but I'd wager it was more to get clean O2 sampling on the rear cylinder instead. A quick look through the '09s and '10s at HD's website just now leads me to believe they've gotten totally away from the old "crossover" setup (maybe since now all the bikes are closed-loop?).
I know my '07 tourer rumbled on decel quite a bit more than does my '09 with exactly the same "stage 1" equipment in service. I rather liked it, but don't exactly miss it either. I'm confident that my closed-loop tune is better as a result.