"the midrange throttle response was mixed"
This happens most noticeably when we pull the snorkel. Thus is seems you have a new intake source. You checked the carb to manifold rubbers. Check the carb to air box rubbers. (I forget if you are freaked or not) Don't you have a drilled air box? Well check to ensure the hole covers are in place too. Also, check the header pipes for leaks at the jugs. (why not eh)
Hum, You might want to pull your saddle to see is you are sucking something into your airbox. Like a strap for a saddle cover...
Just thinking out loud Greg.
