Hia,

comming thursday I have a trackday at Assen Holland. Im afraid my bike produces too many DB's and therefore I wanna take out mij K&N airbox and repace it by a standard one.

Kan anybody tell me if a standard cbr600 airbox also fits into the NC29?

Thanking u in advance!

its unlikely that an airbox mod will contribute significantly to the DB that your bike puts out.
something like a baffle of DB eater in the exhaust may be the solution