What would cause a metal knoking noise when traveling on a 2003 sportster 1200?

Answer 1

I have an 04 Buell Firebolt which has the same 1200 motor as in your sportster. I had an engine knock that was ridiculously loud and even sounded like a rod to me. I thought for sure it was going to need a new motor, but it still had good compression and started and ran fine. (Obviously I didn't ride it like this). After calling around to pretty much every shop in town, I finally happened across a retired Harley mechanic that worked out of his home, one bike at a time, appointment only type of guy. I called him and he said he was 95% sure it was a cam position-er and that it was like $100 out the door to fix it. I took it to him and he fixed it same day. Noise is gone and I was so happy with the guy I bought some oil and filters from him even though I didn't need them. Hard to find a good honest mechanic these days. When you do, pay em well and hold on to them. Hope this helps you out.

I have found that a loose sprocket shaft nut also sounds like a rod knock.