I've recently got myself a XL1200C. It has the baffles still fitted but they have been frigged with, so if I look through the muffler I can see someone has fiddled with 'em. It's not especially loud, but certainly not a stock noise level. At idle it sounds pretty good to me; at say 50 km/h in second gear it is very inoffensive. As soon as you put some load into it the volume starts to increase.

My question is this: how heavy are the cops in Perth on moderately noisy Harleys? My bike looks pretty stock and inoffensive, as do I. Should I have a set of stock mufflers on hand just in case?

you'll be fine, dont sweat it.
just dont' ride down Hepburn Av, flat out, bouncing off the limiter.

Can it happen in Perth , well shit yeah !

One Saturday morning last year ALL the Harleys at Scarboro' got yellow stickered for loud pipes

Most of the riders OVER 50 I may add , so minimal hooning was involved

Myself ( and my mates ) all just missed it , having left 20 minutes before.

2 motorcycle cops who were carrying a "Noise meter" AKA dB reader with them

About the same time some of the Veterans club from Nollamara got busted for noise

That was the last incident I've heard of , so mebbe it's pure luck on my part I've missed it

My own bike is "riddikerously" loud , louder than my mates 120r equipped bagger FFsake !!

Last Saturday 9.30PM I was cought up in a " booze-bus" on the Vincent st north onramp to the freeway , and they didn't mention the pipes at all , although I did hit the kill switch as I was pulled over to the side . Thankfully I'd had no bevvies , just a Jus burger and a coke haha...

Having Stock Pipes / Mufflers spare is a smart move, just in case you have to front a EPA test.