OK, I don't normally ride with the rear window down. 
I was making the point that there was not an exhaust leak.
The exhaust smell should not "knock you down" when you walk up to it when it's just idling.
No it shouldn't. If you don't have any exhaust leaks, I'm not sure what to tell ya. I'd guess that you're running rich, so you may want to just lean it out a tad, or you could be off a bit on the timing, and your exhaust valves are opening before the combustion process is completely finished
