I have a 2005 FLSTCI and have just upgraded to a Screamin eagle hydraulic cam chain tensioner and oil pump and fitted an oil pressure gauge, when I started the bike the oil pressure was up around 40psi, as the engine warmed up the pressure started to drop to a point where at idle the gauge reads 0psi, if i open the throttle a little the pressure goes up to 10psi, is 0psi at idle with a warm engine something to be worried about?

 

Is your engine clattering when the gauge drops to zero? Clatter would indicate no pressure at the lifters. If no clatter you have pressure and the gauge is bad.
Does your oil light come on, if not you probably have pressure at the sensor and the gauge is bad.

 

Is the oil light coming on? If not you're good. Look into trying another gage.

 

Did you check the gage for a piece of debris in the fitting where it goes into the engine?

 

What oil weight are you running?

 

At idle it is supposed to drop to about 5-6 pounds. 0 would be bad, but the engine would be making all manner of noise. Is it possible that your gauge is not reading correctly?

 

Had the same experience as you and yes, it was very worrisome to see Zero pressure at idle. I changed the gauge and got different readings. Harley oil pressure gauges and not precision calibrated instruments.

 

Have an Arlen Ness gauge, at times when idling on hot days, it will read 0. As mentioned earlier, if the indicator light doesn't come on, and no excessive engine noise, your probably ok.....