just changed the oil on my 2000 busa for the first time. took off the right fairing and this sponge like thing with an orange strip on the bottom fell out. wtf is it? do i really need it? if so where does this thing go?
It is probably one of the foam bits that are attached to the inside of the fairing. Take a look at the fairing and see if there is a place that the foam looks like it came from. Then glue it back on.

It is probably not critical. I think they are mostly there to prevent rubbing, vibrating, and to prevent air from getting around the radiator instead of through it.
Just stuff it back, orange side to the engine. It should fit snuggly between the hose and frame part. No need to glue it down to the fairing.

It's not really necessary, I've forgotten mine quite a few times with no problems. :thumbsup: