Topic: Oil Pressure Light Always On

[alfluvah]

Hey everyone, just checking in with those more knowledgeable to see if I'm on the right track.  My oil pressure light has remained on and will not go out.  This started right after I replaced the left side gear cover on my '74 CB750K.  Once I buttoned everything up to take a short ride for leaks I noticed the light went on.

I disconnected the wire from the sensor and the light did not go out so I assume there is a short.  It looks as though the sensor wire runs through the left side engine case where I was working so my guess is the short is there - does this make sense?
There were wires tucked into the upper part of the case pretty tightly and my guess is that something got pinched when I closed up the cover.  Does the engine oil light sensor wire run through this case - the charts seem to indicate it does. 

Sensor is clean and checked tappets and sensor hole - oil is moving well and levels are fine.  Connections in light bucket look good as well.  Like I said, everything was fine with light function until the left engine case was opened and buttoned up.

Thanks!

[70CB750]

Seems like you already answered your question

Gotta get back in there and find the short.

The wire from the sensor goes in alongside the starter, joins wires from alternator and Neutral light and is part of the big 6 connector between the engine and the electrical harness.

[alfluvah]

Seems like you already answered your question

Yeah, I know.  Gut check.  Pretty sure something was shorted when stuffing the wires back in.  Just didn't want to open up the case again, but at least I don't need to go hunting elsewhere.

[Kenzo]

Nob question, say the oil light goes on during a ride...

...what is the simplest way to confirm oil flow (VS a sensor issue)?

TIA,
Kenzo

[70CB750]

Pull tappet cover on each side - you will need 17mm box end wrench to do that - and the oil should be coming out quite a lot with engine running.  That will make you sure the oil is delivered to the top end.

[PeWe]

If lamp is lit and engine sound really bad after some driving, the sensor and lamp are functional.

[Mantree]

Oil light is a ground sided switch so you are grounding on the case somewhere ether trace the wire in tell you find it or just run new

Sent from my ME302KL using Tapatalk

[Kenzo]

Pull tappet cover on each side - you will need 17mm box end wrench to do that - and the oil should be coming out quite a lot with engine running.  That will make you sure the oil is delivered to the top end.

Thanks

If lamp is lit and engine sound really bad after some driving, the sensor and lamp are functional.

ha...I'm pulling over if the light goes on!


Cheers

[alfluvah]

Oil light is a ground sided switch so you are grounding on the case somewhere ether trace the wire in tell you find it or just run new

Sent from my ME302KL using Tapatalk

Bingo! Wire was exposed and touching block. All fixed. Thanks to all!

[Restoration Fan]

Nob question, say the oil light goes on during a ride...

...what is the simplest way to confirm oil flow (VS a sensor issue)?

TIA,
Kenzo

Well, IMO, the simplest way is to check the oil pressure gauge that you installed in place of the oil galley cap on the right hand side of the bike.

Ron

[seanbarney41]

everybody remember...presence of oil pressure does not guarantee its getting to the cam, and oil in the cam cover does not guarantee you have adequate pressure for the crankshaft, but if you have both you are good

[70CB750]

everybody remember...presence of oil pressure does not guarantee its getting to the cam, and oil in the cam cover does not guarantee you have adequate pressure for the crankshaft, but if you have both you are good

You are quite right, but he asked for the side of the road check.

Crankshaft bearings typically do not cause catastrophic failure on the road.