Ok, I've got an update.
Tore the carb apart the other night. Finally got the Float pin out, had to drive my pocket knife under the pin head to get it to come loose. Hosed out the carb with a can of carb cleaner, installed new needle, seat and 153 main jet. Checked diaphragm (was good, thankfully), and checked throttle needle. Removed emulsion tube and cleaned, made sure all little holes were open.
Reinstalled carb and installed a K&N filter.
So far, so good. Have noticed a slight hesitation as the throttle opens, but clears up and accelerates well. Loads up a little bit at lower RPM's. I have picked up a little speed and acceleration, but not as much as I thought I would with the bigger main jet.
I left the pilot jet at 140. Any suggestions on a better combination?
Thanks for the info too.