At the Westwood club tonight a rider/tuner that has checked found that his bike made 2 HP MORE after a fresh muffler repack than before it got new woolies tucked in there. And I'm not talking about the totally hollow Muzzys here. This was a race bike that needs to pass the noise testing. So it still had packing but it was beaten and loose.
So for all you guys that think you'll make more power by removing the packing it's time to think again.
Imperial had a bag of proper muffler coarse strand stuff for $16 I think it was. It was cheap anyways. So if your can is more than a few years old then repack it and enjoy the reclaimed power while you hide your head in shame at having made the neighbours happy.