I can't say for sure but I think I red somewhere (when I was reading up on the FCR carb tuning stuff) that in a situation like your it is running way rich at that moment when you crack the throttle.
The only issues I see in the above would be that it didn't don't before this season.

Didn't someone here recently have a similar issue... Cleaned the plugs and all was well,again! How do your plugs look?

SOLD: 07 Black BA, 39mm FCRs, TPUSA stage 1 head, TPUSA 813 cams, TPUSA 10.8:1 pistons, TTP #3 igniter, Specialty Spares Long Cannons, Tsukayu Hard Bags. 82HP/55tq NEW: 19 Goldwing Tour DCT