With your setup it sounds like your too lean...those pipes and ac will pull your AFR off..try an Xied before you ruin the motor. They are cheap and effective for what your experiencing.

 

Now my question is. I have a trip to the smokies coming up this weekend. If octane boost fixes the ping do you think I'll be ok using that to get me by till I can get a tuner?

 

i think so

 

so many things can cause a metallic rattle at certain rpms. some internal and some external. Internal: what year bike? I don't think you mentioned. How many miles? If 2006 or earlier, the cam chain tensions could be worn enough to throw off the cam timing a bit. could be in the primary, a little chain slap. You have slip-ons and a freer breathing AC. do you have HD's stage 1 download? you can invest in a tuner, in Xied's etc or pop over to your dealer and have them do the stage 1 download (I know, not the best, and will maintain EPA compliance (i.e. Lean)
External: most have mentioned heat shields. I've chased down some external rattles in the past and over 115,000 miles (2 bikes) I have found the following:
Rubber bumper on jiffy stand (older models the rubber was on the frame, newer on the stand) was missing causing the jiffy stand to vibrate against the frame. Another time, my clutch cable adjustment was off (too much free play) and the clutch lever was rattling at certain rpm. Another was my windshield bag rattling against the windshield. Another was shift lever rattling. the list can go on.
You say only happens in 4th and 5th gear - if it is rpm related, you'd hear it in any gear.

Sometimes mine will just make a noise for while and then go away... i've learned to live with it sometimes.

 

you need a tuner on that bike prior to doing a long trip up mountains. That elevationwill lean that bike out even more. The CFR knock-offs and the real thing are tough to tune with how big they are. Not having a tuner is asking for trouble.

Good news is, the tuner is a simple quick thing to get you going. Find on your way and plug it in. Put a basic map with your mods and use it.

 

check that you didn't lose one of the flange nuts; where your exhaust pipes attach to the heads.

 

Just a shot in the dark. Had similar noise. It was caused by loose rivets and cracked bracket mount on my Pro Pad Mini Beast 2 air horn.

 

Forgot to mention. It's a 2011 street glide with a 103. Almost 19k miles. Compensator already replaced. I put in some octane boost from my local gas station. Didn't help much. Maybe just cheap crap. Anyway called the place that did my compensator and he's going to check it out Monday. If it is engine ping he'll sell me a SEST for $405 out the door with free downloads any time I need them. Only about $200 more than a download so I figured what the hell.

 

I think your on the right track, the tuner will help you. Octane boost would not be the answer..

 

1 Bottle of Octane Boost will increase the octane rating in your tank by about .01% regardless of what it claims to do on the label so that is definitely not going to help you out. The tuner will.