Motorcycle Repair: oil light-no pressure, oil pressure gauge, oil pressure switch

Question
QUESTION: I just bought a 97 heritage softail with 9000 miles on it.I put 1200 more miles on it then noticed the red oil light coming on.I put in 3 quarts of harley 20/50 and a new harley oil filter,the light is still on.I don't have an oil pressure gauge on the motor so i relly don't know whats happening.the top end seems abit louder then when i got it.Bad pump,plugged oil passege,faulty sending unit for light?Thought i'd start with a gauge to quiet my paranoia.the bike still runs strong but sounds like my pan did when it wasn't getting any oil to the top end.Clickaty clackaty expensive.Thanks for the advice.

ANSWER: Does the oil light come on when you start the bike and stay on until you shut it off or is it on intermittently.

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QUESTION: As soon as i turn on the ignition the light comes on.The whole time it's running the light stays on,does not go away till i shut off the ignition with the key.If the powers on the warning light is on.Does not come and go which is why i was hoping for a bad sending unit or something along those lines.It's a small problem i'm hoping to catch before it turns into something major,thanks for trying to figure this one out for me.

Answer
Either your bike has low or no oil pressure or the oil pressure switch and acceding wiring is bad. Lets go for the simple and easy first. The oil pressure switch on your bike is mounted on the back end of the rear cylinder on the cam case side of the bike. This switch operates by when there is no oil pressure or not enough it closes with causes a ground to be sent to the oil light in your dash the oil light has a constant 12 volt signal to it, its just waiting for a ground signal to come through the wiring from the oil pressure switch to make it light. So if you unhook the wire from the oil pressure switch and turn the ignition switch on and the oil pressure light comes on then you know the wire between the oil pressure switch and the oil dash light is worn through some wheres between the switch and the light causing a ground, Happy hunting. But if the light does not come on then I'd pull the oil pressure switch out and roll the engine over if it starts shut it right back off if no oil comes out of that hole you probably have a sheared key in your oil pump but if after a few seconds oil does come out and its spuratic at first and then good flow you probably had a air bubble in the passages in the cam chest and now you've just burped it, reinstall the switch and hook up the wire and see what you have when you start it.