1998 HR Road King with 96" S&S Evo motor, 55k miles on motor. Runs strong, but when I let off the gas it makes a god awful metallic thrashing sound, like there are two or more metal surfaces vibrating against each other. If you get on it the sound goes away completely, and this occurs in all gears, mostly noticed when decelerating or if I sit in neutral and rev, it is noticeable.

 

Welcome to the site.

 

Check/ adjust the primary chain tension..., and tensioner


Ghost

 

What he said and Welcome to the hood

 

Even though it’s a RK we won’t hold that against you. Lots of very knowledgeable people on the dyna side...

 

Id be checking the compensator sprocket while you're in there looking at the Primary tensioner.

 

I had a similar issue and it wound up being a loose baffle.

 

Welcome, check your heat shields or just replace the clamps for the heat shields.

 

I have been battling a similar issue. Almost like a heavy sewing machine noise letting off throttle. Dealer says cant replicate. No information in forum search. Fluids correct and not an outside noise such as a heat shield. Feels enternal. 08' wideglide. Following.