OIL LIGHT is always on

Hi; I just restored my 1973 z1, the engine was rebuilt completely. But for some reason when I run the bike the oil light is always on, and the bike makes rattle sounds coming from the clutch basket at idle only. How can I test oil presure or how can I check if the light is not working properly. Thanks for the help

Check your wiring diagram. If the Pressure Switch is intended to go to chassis/ground when the pressure is low like mine then do the following:

1 - Disconnect the wire at the Pressure Sensor,

2 - Turn the Ignition Switch ON,

3 - Take the wire and touch the engine,

4 - If the light does not turn ON then the Oil Light circuit is faulty. Be prepared to troubleshoot and replace the wires, connectors, bulb holder, bulb, +12 Vdc from the Ignition Switch, Ignition Switch, feed wire from the Fuse Box, Fuse and or Fuse Holder contacts.

5 - If the light turns ON then the Oil Light circuit is OK. Be prepared to replace the Oil Pressure sensor.

Also, be prepared to test the oil pressure and if low be prepared to change to a thicker grade of oil within OEM range or change the Oil Bypass Valve or the Oil Pump.

See the typical KZ Engine Oil Flow Diagram below:



Best of success.
Bill

Let's try that Oil Flow Diagram again:



That better. :laugh:

Cheers,
Bill

Double ought, one thing Bill neglected to clarify in his very good explanation:
If the oil pressure sender electrical feed wire between the indicator light and the sender is touching a ground anywhere (i.e. the frame or engine), the light will come on and stay on as soon as the key is turned on....even if you have full oil pressure AND a good oil pressure sending switch. You MAY have to find where that wire is possibly grounded by following the actual wire. The wiring diagram is a huge help when doing this kind of thing.
A quick check for this condition can be done by disconnecting the wire at the oil pressure sending switch and making sure the ignition key is OFF and preferably having the battery cables disconnected so you don't fry your meter by accident.
Get out your ohmmeter, set it to the lowest ohm scale and hook the red lead to the wire you removed from the sender, making sure that the lead and the wire are NOT touching anything on the bike. Then hook the black lead to a suitable bare metal ground on the frame. You should NOT
SEE ANY READING on your meter. If you see any reading on your meter (i.e. zero ohms, 1 ohm, etc.) then the wire between the sender and the ignition switch is grounded to the frame somewhere along the way. Check for a partial ground by using progressively higher scales on your meter. Each scale should show NO reading at all.

What say, Lou ??? Did I nail it ???

00. wrote:

How can I test oil presure

They make low caost oil pressure gauge kits with the adaptor fittings that screw into the same hole the sending unit goes into. I got one for my 750 twin from JC Whitney. That will give a reasonably accurate pressure reading.

I recommend getting a gauge just to make sure something didn't go wrong in the rebuild. My engine has a pressure "relief" valve on the out side of the pump which would cause zero pressure if installed wrong.

I still remember back in the 60's we got the engine in our MG rebuilt by a guy and when we put it in the engine ran good but the gauge showed no pressure..... guy said the gauge must be defective. Long story short, he had the oil pump wrong and the engine had zero pressure and destroyed all the bearings in short order.

Better safe than sorry.

Hey H2RICK, IMHO that possible short-circuit idea is a good one!

I wouldn't be surprised if that's his main problem.

Bill

Well, Bill, it wouldn't be the first time that someone had a bare or pinched wire grounding out. Of course, I wouldn't have any personal experience of such an occurrence.... :whistle::laugh:

H2RICK, nudge, nudge... wink, wink... say no more. :whistle:

Cheers
Bill