I sympathise completely with that view, both regarding the speed and the noise. The usual defence of "Loud pipes save lives" is pure BS in my book. +1 
Loud pipes are yelling "Look at me on my amazing Harley" or Chook Chaser or whatever.
While I'm on this rant, can Roper or Tackle tell me how these idiots get away with these straight through pipes? There are quite a few cars with minimal silencing around too. Is it too hard to police or is it a matter of priorities?
Biggles quite simply it comes down to three things:
1. Australian Standard requirements for testing at specific rev limits and quite a few of these bikes simply don't have tachos to allow for testing in compliance with Australian Standards when we do have the equipment in calibration. (internal issue - money) There are also different interpretations of what equipment is required for testing. I know myself, and quite a few traffic fellas, have the opinion that we don't want our integrity questioned in Court for when we arrive with more 'serious' matters and are very cautious when these types of questions are raised in Courts about whether we are following the correct procedures when dealing with motorists. Until these issues are sorted and everybody is on the same page (which is required as far as I'm concerned) we don't want to plough head on and be criticised in Court because we were blindly following what we're told to do without questioning the procedures are correct to ensure we are following legislation.
2. The second one we deal with is the wording of legislation in relation to penalising people that perform the modification and the investigation required to prove who did the modification. Most Harley's leave the factory with standard pipes that comply with world wide noise limits, however before they leave the dealer there is a modification to pipes that don't comply, as Terry said. Most people believe that these pipes comply because they buy the bike like this and sound level testing is not part of the Safety Certificate (insert whatever your state calls it here) for registration so they don't understand why they can have a registered bike that doesn't comply with legislation because of the "That's how I bought it" defence. Most people don't understand that the safety/roadworthy inspection in most states and territories only covers about 40-50 points to pass.
3. The other issue we have faced with this is that a lot of people don't understand that there is two types of undue noise, causing losses in Courts when legal boffins create confusion for the Magistrates and junior officers not knowing how to stand up and correct the dribble. The first type has to do with the old spinning the wheels on the road, or revving the engine at the lights etc and the second has to do with the noise emission testing in compliance with Australian Standards. One is linked to the other, however testing separates the two for prosecution purposes.
a) The first is purely a subjective test - Is the manner of operation causing the noise emitted required as part of normal operation? Eg Did you have to rev the crap out of your engine as you spun the tyres across the intersection at the lights leaving a dirty great big friggin mess on the road you peanut?
b) The second has to comply with testing procedures set out by the Australian Standards when determining whether it complies with legislation. Eg Maximum output of a vehicle happens at X revs and Australian Standards require a vehicle to be tested at Y (=75% of X) to meet a certain dBA level.
b) is purely done by compliance testing & a) is done by the lose nut behind the wheel showing off to his mates in public.
Terry i also know of at least three bikes around Townsville that have stamped pipes that have had baffles taken out by various owners. I can take my antenna off the bike and poke it up the muffler to show there are no baffles, but that is not a scientific test for the Courts apparently.
As for the difference in Filtering and Splitting bike riders are the only ones that are specific in what they mean, if you talk to my bosses there is no difference. One is what people here refer to as filtering, the other is dangerous operation of a m/veh (at speed), or illegal/unsafe overtaking, and this is what is shown in the letter posted.
