Thanks for that tip. Just for reference here are pictures of the stock right and left side mufflers looking up the inside from the rear. 2010 Road King Classic.

Right side. Kind of looks straight through but the exhaust flow must go through the little holes around the sides before it can exit the muffler. Has that low pitched percussive Harley tone that sets my left ear on fire.


Left side. This side is pretty quiet but the exhaust pipe configuration doesn't let as much reach this side so I don't know if it's quiet because of the muffler or the pipes.

 

Update - I bought a set of stock 2009 touring mufflers and installed them on the 2010 Road King this week. They make my bike much quieter. Almost as quiet as a BMW. There's probably some loss in performance but I'm willing to accept that. I also got fitted for a set of vented custom earplugs at my audiologist but haven't received them yet. The vented earplugs eliminate the "boom box" syndrome I feel with tight sealing plugs. I'm pretty sure the combination of a quieter bike and more comfortable plugs is going to work for me.

 

Sorry these took a while, they were under the house. I see you seem to have solved it but I thought I would post anyhow just for others future reference. These pics are of the left side muffler on my HDI Australian spec bike.

The bike had a valve in the exhaust that shut off the right muffler and sent all the exh to this muffler when you got on the throttle. this muffler is super quiet.

 

Probably should have cleaned up the bench before I took those....

This is the right side muffler. Looks the same as yours.

The other photo shows the headers and the flapper valve.

 

Check with your dealer, I think if you put HDI active mufflers on a US bike your electronic brain needs to be reflashed since it is what runs the active portion of the mufflers.

 

I was not suggesting that you run the headers and flapper, its pretty stupid. I just included it for completeness.

 

Just an FYI, the Touring Family mufflers for Japan contain a catalyst in the muffler rather than in the head pipe, and the outlets are about half the size of the US-spec touring mufflers. They are whisper-quiet.

 

does that mean that your stock 2-1-2 system doesnt have a cat in it?

That would be worth something!!

So getting rid of the cats just means getting different slip ons? Lucky.

Does it have the flapper?

 

No flapper, no cat in the header. Only have to change out mufflers to get rid of the cat on Japan-spec Harleys.

 

Thanks for the info on the international exhaust systems. I guess the fact that the Australian models need a flapper valve/active exhaust would rule them out for me. The Japanese mufflers might be promising. Do they require the flapper valve style head pipes with the electric control?

The stock 2009 mufflers made a big difference and they probably are going to solve the pulsing tone that gave me tinnitus (although the tinnitus stays for life apparently). Actually I bought a set of 2008 mufflers too but didn't use them. I arranged to buy the 08 mufflers first but a set of 09's became available before the 08's got here. They look the same but nobody has been able to tell me whether the 08's have a cat inside them. With the 09's I have two cats back to back, one in the head pipe collector and then another one in each muffler. I don't see any difference in oil temps so I doubt this is hurting the motor even though it probably reduces performance a little.