I'm thinking I've got an exhaust valve in the process of being sucked, Ha! Theres a popping noise coming from the rear cylinder exhaust, and a new tapping sound at speed...I've rode this 87 FXRC since new, My first Hog, never had any top end probs in about 83K miles...this noise sound familiar to anyone?
Dismal

 

I had a similar problem at about 80K miles on my last bike. Ended up having a valve with a pin hole burned in it. It was caused by a crack in the intake manifold gasket, which created a lean condition.

 

So a top end/valve job hooked ya up then?

 

yea, i'd yank the heads and do a valve job...while your at it, pull the jugs and hone & re-ring it with new gaskets...easy and youre already there

 

Roger that! The popping noise sounds like a valve for sure...kinda like the sound a chick with full lips makes when she opens her mouth! Ha!
Dano

 

What he said for sure.

 

And while you're there, put new lifters in. They're already running on borrowed time.