I have a 94 Ultra Classic that has low voltage output when the engine speed is at idle. Could this be the Voltage Regulator or is it the Stator? I bought this bike 7 years ago and have always had this issue. I have had the bike apart for a few years however it is back and running great now except for this and an Oil Pressure issue at idle also. Is there a way to test the output of the Voltage Regulator or the Stator separately? Do I have to replace both Stator and regulator together if one of them is bad or can they be replaced separately?
The Oil Pressure issue is that when the engine has been running for a few hours, and I stop at a stop sign or light, the oil pressure drops to below 10 psi and the Oil Light comes on. I have to rev the engine a little to keep the pressure up? I bored out the cylinders 20 over and have high compression pistons in it now. I did not do anything else to the engine. Should I replace the Oil Pump and if so is there a High Pressure or High Output Oil Pump and if so what one should I put in?

Thank You,
Steimi

 

That is absolutely normal for ANY Harley engine. Ride it.

 

How low is the voltage at idle measured with s DVM at the battery?
Stator and VR can be replaced separately if only one tests bad.
Charging system testing instructions are in stickies in electrical section.
That's normal for oil pressure on HDs, I think 6-8 psi is normal hot idle pressure per manual.

 

I was told this many years ago and probably still true. You can take a brand new motorcycle off the showroom floor, start it up, leave it idle and it will drain the battery until it eventually dies. The charging system does not put out enough to charge and run the bike at idle. That it takes about 15 minutes of driving at highway speed (engine at operating rpm) for the charging system to put back the charge into the battery that it took to crank that bike up. This is what I have followed for the last 37 years.

 

Evo's have low oil pressure at idle. However you idiot light should not be coming on. You need to put a gauge on it to see if it is in fact low, or if the light may be malfunctioning.

 

Hi from the UK and welcome to HDF. We have a Tech Electrical section where you will find two Stickies, with instructions on checking your charging system. If you have any dounts follow them to identify any actual problems.

What is your engine idle speed set at? It should be around 1,000rpm, if it is just a little lower the light may come on.

We have a dedicated Evo section, where you can meet up with current owners, so pop in over there.