I have a 2017 Harley Ultra limited with 24,000 on it since new and just heard from dealer that I need a top overhaul. Talking with the Harley service rep he asked what RPMs I was running the bike. Kind of telling me I wasn't getting the engine hot enough to burn off fuel causing a build up of carbon on the valves. I stated I couldn't remember off hand but that most of the miles were on long rides lasting from 7 to 8 hours on major highways. Just wondering if other M8 owners have experience anything as this.

 

Ask them to show you the valve seats and guide seals. Could be that, certainly not unheard of in first year M8s

 

What are they symptoms, that lead to that diagnosis?

 

Why was the bike in the dealership in the first place? Was it consuming oil? Have compression and leak down tests been run? Dig deeper before you dump a load of $$ on a top end rebuild. Like Nomad Max says, could be heads just need some work; if there is some carbon build up, there are ways to burn that off or it can be removed while the heads are being worked over.