It seems like when I start my 2001 Fatboy I hear a slight nocking in the motor at RPM. once it warms up it seems to go away. I have been told it might be the compensator? How do you tell if it is the motor or the compensator?

 

I meant to say low RPM. Bike has 55k on it. Runs great no smoke no burning oil.

 

2001 typically don't have compensator issues, ( that's an '07 and later trait.)

I'd be looking at old, weak 55,000 mile lifters that aren't pumping up too quiclky anymore.

 

Doesn't sound like lifter noise. Sounds more like deep low frequency sound. Once warmed up sounds fine sounds fine. Do these motors start knocking gradually or do they typically just let go?

 

Have you changed where it idle's. Without hearing it I would have said lifter or its almost due for an oil change.