Hoping someone can help before I tear down the engine on my 99 Buell X1 lightning...I have a loud knock when bike is idling and sounds like it's coming from the bottom...it can be heard from far away and is embarassing when I'm stopped at lights. When I accelerate, it doesn't seem to have power and he upper motor assembly (valves, etc.) become noisy and just doesn't sound right. I read about it possibly being compensator nut, and I was wondering if there's a way to verify prior to taking primary cover assembly off. I already tightened my primary chain to specs. I tried to wiggle sprockets through inspection cover hole and they seemed tight. Does a loose compensator nut really sound like a loud knock? I know these bikes have noisy valvetrain, but sounds really crappy when i get on it with the throttle...any thoughts?

If the engine sprocket nut is loose you should mainly hear that from the left side.

I had a bad small end bushing and it made a matalic tapping sound from the top end.
I had a bad big end bearing on the front rod. It made a knocking sound from the center of the motor.

Lifter(s) are bad.