Cb750 oil pressure light OFF.

[el__burro]

I'm putting the wiring loom back on the bike (k2)
My hurdle is that the oil pressure light stays off when I turn the key.
No isssue with Neutral light.

90% sure it's no wiring issue.
Can it be the switch itself? How do I test it?
Any other suggestions
Thanks
El__burro

 

[coyote13]

Check the bulb first, I've had a few go out on me

 

[Sonreir]

To test the switch, unplug the alternator from the harness. Read the resistance between the blue/red wire and the negative terminal of the battery. If you get a low number (under two Ohms, but under one Oh would be better), then your switch is working. If you get no reading at all, then it might be the switch, but it could also be the wires or the ground connection.

 

[el__burro]

Cb750 oil pressure light OFF.

thanks both.
bulb is ok, i swap it around with neutral and its fine.
i have no resistence (or Biiiiiip) between wire and negative battery.
i also tried on the switch itself.
only when I touch the outside part of the switch it beeps ( i guess its normal)
i guess its not working then, how do I remove it, (26 spanner?)

thanks
el__burro

 

[Sonreir]

Probably the switch. Been a while since I've worked on a 750, but I think there's just a 10mm bolt holding it in and then it pulls out? Someone please correct me if I'm wrong.

 

[el__burro]

is that the only to test the switch?
i guess i just need to unscrew and try a new one.

 

[el__burro]

maybe it has nothing to do with this but

I have both wires to the kill switch disconnected but still i am able to start the motor.
thanks
el__burro

 

[Sonreir]

maybe it has nothing to do with this but

I have both wires to the kill switch disconnected but still i am able to start the motor.
thanks
el__burro

You mean turn the engine over with the starter, or does it actually start and run?

 

[el__burro]

Ign on + push button engine starts.
Ign off + push button motor turns (engine doesn't start)
Is this regular?

Thanks
El__burro

 

[mydlyfkryzis]

No. Start circuit is supposed to be on the switched ignition circuit, not on a power all the time circuit.

 

[el__burro]

i am confused, on a specific honda sohc i was told differently about this.

 

[Sonreir]

Ign on + push button engine starts.
Ign off + push button motor turns (engine doesn't start)
Is this regular?

Thanks
El__burro

I think you mean the kill switch, not the ignition switch.

Starter button should not work with the ignition switch off, but it will work with the ignition switch on and the kill switch off.

 

[el__burro]

You are right. In other words the kill switch doesn't kill the starter motor.
Trying to do more tests on the oil pressure switch. Light doesn't come on. Oil is fine. All wiring too.
Thanks
El__burro

 

[el__burro]

Which oil pressure switch is suitable for my cb750 k2?
They all look the same to me.
are this one ok?

Thanks
El__burro

 

[Sonreir]

That's for a DOHC. I'm not sure if there is a difference in the part, but make sure you have one that's for the SOHC.

 

[crazypj]

The thread is pretty standard, I think 1/8" BSP? (Honda used a lot of Imperial threads back then)
Personally I would try and get hold of a switch with a higher than 4psi 'off' position and wouldn't even consider a used one off 'fee-pay'
In one year I had 5 go faulty on my CB550F1 while it was still under guarantee (a long long time ago -1977 8) )
Try any of the auto shops, automotive switch is pretty much exactly the same thing, finding one small enough shouldn't be a problem
I'm pretty sure I've seen them in Pep-Boys
Oh, to check switch, it should connect to ground when engine has been stopped for 2~3 mins
Just use meter from centre bolt to body, low ohms or whatever your meter does for continuity