by Brian FZR400 » Wed Feb 01, 2017 1:28 pm
The word "effective" is subjective unless quantified by a repeatable test procedure.
"Sound-attenuation material or devices" is open to interpretation.
Is it necessary to require exhaust outlets to point to the rear? Where else would they go?
I don't have a problem with disallowing open pipes or megaphones but I think it would be better to implement a defined test procedure and put those requirements in the rules, and how you achieve compliance with that procedure is up to you.
Forewarning; the official procedure that Calabogie uses for sound testing in the paddock is marginally passable by modern liquid cooled 4 cylinder bikes with common aftermarket mufflers. Singles and twins are louder, two-strokes with tiny stinger mufflers are a lot louder, air-cooling is not a positive factor, not having full bodywork is not a positive factor. I've known people with modern bikes to have to put stock exhausts on there, and lots of people with the usual Hindle mufflers have to install an extra gizmo in the muffler to restrict it a bit in order to squeak by. I spun my Hindle muffler 180 degrees to point the outlet upward. Let's perhaps not discuss, ahem, "tachometer inaccuracy" or "throttle position inaccuracy" in order to be able to get on track ...
I know in practice Calabogie used drive-by testing (basically a trackside test station somewhere) but this is not something that someone could know whether they are compliant or not before getting to the track. It seems to be a whole lot easier to survive the drive-by testing than the paddock testing (which we didn't have to do).