hey bud,
i have a genuine 05 thumpy also and i was washing mine on the weekend and the exact same thing happened. I washed the air filter out, and also when i took the air filter off to clean it i found that there was a rip in it about 1/4 the length of the rubber section when u put it on to ur carby, so i got sum electrical tape and that fixed that promblem, then i washed the air filter out..and tryed starting it..you could hear it kicking over, but jst wasnt starting..left it for about 10mins and it started beautifully...so hear is my advice:
check that the air filter has no rips. (cause if it has rips the motor may not be getting air)
clean the air filter
thats wat fixed mine so hope it wrks for you to, also my mate has an 04 genuine thumpy and the same thing happened but he left his over night and the next arvo it was all sweet.so good luck mate