I have a 113ci Kit put on by the local HD Dealership that when it is warm and we are decelerating, makes a slapping sound. The kit has a compression release style head but the sound is getting louder. At first sounding like a vale lash issue. Now a slapping sound. Under acceleration there is no sound. Anyone know where I should start?

 

Start back at the local HD dealer that did the work.

 

Might want to take a peak at the primary chain and/or it's tensioner.

 

And don't let them tell you "this is normal".