95 fatboy knocking in the engine?

This harley knocks. It doesn't get any louder under a load and does not miss. It sounds like a lifter has gone flat but no miss even at high rpm's. Ihave put several hundred miles on it since I bought it. It sat for about 4 Yrs before I got it. The mechs at the shop said to drive it for a couple of hundred miles and see if it would go away. No luck. I'm thinking it has solid lifters. It does run strong but is no hotrod. What does Mr. Willy Nilly think now? Thank you!