As you can imagine, most scooter owner/operators are very interested in having the best possible exhaust note from those 250cc monsters. With exhaust pipe diameters about the size of an average drinking straw (possible boba-sized) this can be tricky.
I do like this guy’s solution, though. Sure, it adds a good bit of weight and some aero issues, but you can get quite a great dynamic range of sound out of the system.
Contact the author at firstname.lastname@example.org.