Have an 09 Fatbob. Running down the highway in 5th or 6th I twist the throttle hard to make a pass and I hear for a second or 2 this tick, tick sound. Bike runs fine and has all the usual sounds a HD will make. This sounds like hot exhaust hitting the cooler air of the exhaust manifold or bugs being fried on the front of the front pipe. I can tell it's not internal, it's external for sure.
Anyone else have this noise?

 

pre-ignition
Caused by low octane gas or too much throttle in higher gears when the rpm's are not high enough (lugging).
By doing this you are beating your rod bearings to an early death.

 

I use only high octane fuel. I never lug the thing, I keep it on the pipe most times. Like I said...only when I hit the throttle hard when I,m making a pass.

 

My wide glide will rattle the gas cap a bit when I get on it, could that be it?

 

Get your rpm's up higher and try it, everybody has their own idea of what lugging is, your bike might have other ideas.
What does "I keep it on the pipe most times" mean?

 

I have flush mount gas caps. It's definatly up front on the motor and only for a second or 2. Like something is hitting the motor, it has no specific rythym. When I gas it hard it's there and if I keep it at that speed it goes away till I gas it again.

 

Keeping it on the pipe is a motocross term meaning the revs are up.

 

something loose....

 

I figure if something was loose I'd hear it all the time on a Dyna.
Anyways I can't find anything loose.

 

You know the sound that a bike makes after you shut it down and it cools. You hear the metal contracting. It ticks, stops and ticks again. That's what I hear. 3 or 4 ticks but only when I get on it hard in 5th or 6th gear.