Had a similar noise on a brand new Sportster back in 2000. I thought it was engine related and checked all kinds of stuff before finally taking it to the dealer. They had it almost 2 weeks before they called me to come pick it up. Turns out it was a loose horn bracket allowing the horn to rattle on the frame.

Moral of the story?- Start with the simple stuff before you go tearing into it too deep.

 

If it's been there for years don't worry about it, just ride.....

I have a noise that sounds like you are shaking a paint rattle can when I am in 6th gear...been there since I bought the bike used 15,000 miles ago. I'll just spend my money in one shot if something changes drastically instead of spreading it out chasing stuff.

Jim

 

I took me weeks to find my chirping noise coming from the rubber buffers on the rear muffler mounts. Just about drove me crazy.

 

Probably not your problem but my 07 RK had a squeak when you slowed or braked. took me a year to figure out it was the front of the seat where it goes into the slot. Good luck