Problem solved! Here's what I did: 1. Replaced the accelerator pump spring. It sounds like I overpaid, but this one is a nice shiny red color. You can't beat that for $20. 2. Swapped out the needle for NCVS. Clip 4th from top. 3. Dropped the main jet to 162 4. Bumped the leak jet to 50 5. And even put a nice shiny tire on the rear A couple of laps and she was popping on decel. I swapped out the 162 main for a 168. Oh baby, she started purring like I always knew she could. I opened the fuel screw another half turn for a total of 2.5 turns. Bumped the idle a couple of notches, and that poor rear tire didn't know what it was in for. No more bog/sputter/whatever under load. And no more off-idle bog when quickly opening the throttle! Thanks for the patience and many suggestions, it feels great to have her running like the beast I knew she could be!