TOPIC:

KZ550A3
Looking at the Archived messages, I see that someone had exactly the same issue I have with the oil light, which stays on even if the engine is not started.

Comments from the post (put a electronic ignition on (NOT MY CASE), the blue wire for some reason is too close to the plate....Sure enough, the plate was rubbing the wire and shorted.)

He solved it.
Does anyone know what do they mean with the "plate"? Where is it located?

Thank you!

Eneko wrote: KZ550A3
Looking at the Archived messages, I see that someone had exactly the same issue I have with the oil light, which stays on even if the engine is not started.

Comments from the post (put a electronic ignition on (NOT MY CASE), the blue wire for some reason is too close to the plate....Sure enough, the plate was rubbing the wire and shorted.)

He solved it.
Does anyone know what do they mean with the "plate"? Where is it located?

Thank you!

The problem discussed only happens on 650's, not 550's. The 650 has the oil switch under the ignition plate., which, if shorted, makes the light stay on when the engine is running, even if there is adequate oil pressure.

The 550 has the oil switch located on the oil pan. The oil light should be on whenever the ignition is turned on and the engine is not running. So your reported symptom is normal. It should turn off when the engine is running.

Do you mean to say the oil light is on even if the ignition key switch is turned off? That is not normal.

Thank you!

The oil lamp is lit, indeed, when the ignition is turned on but it stays on when the engine is running.
I did not finish putting all together yet (headlight) and, only drove 200 meters with the bike (but I am also worried about the possible damage).

When the engine is on, I unscrewed both oil cooler tubes (a little) and noticed that the oil is flowing through the cooler.
I replaced oil (10/40) and filter and cleaned oil pump filter as well.

Check that the wire from the switch is not grounding somewhere. The oil pressure light on these use the switch as a grounding wire. So there is always a positive 12 volts going to the idiot light. The oil sending unit (switch) is closed when there is no oil pressure so the idiot light turns on. When there is oil pressure the switch goes to an open circuit which turns the light out. So anytime the wire from the sending unit is grounding on something then the light will stay on. I have seen this a lot over the years especially on older bikes.

I was on the road once with my KZ900 and had a dealer change the oil for me. He put in 10-30W oil and the light stayed on - even at higher RPM's! I took it back and he said it was normal.????? I insisted they do it again with 20-50W and that solved the problem.

Thank you Toolmaker!

It sounds worth trying. I read about more people having solved it this way.

Cheers!

Toolmaker is talking about a KZ900 bike. That engine uses roller bearings on the crank so the oil system on that engine is low pressure around 3 psi. The KZ550 uses plain bearings on the crank so the oil system on that engine is high pressure. If the oil light goes off with a simple oil change on the KZ550 then something is wrong with the bikes oiling system such as bearing clearances are to loose or the oil pump is worn out. Changing from 10/30 weight to 20/50 shouldn't have any effect on oil pressure if the engine is healthy.

baldy110 wrote: Toolmaker is talking about a KZ900 bike. That engine uses roller bearings on the crank so the oil system on that engine is low pressure around 3 psi. The KZ550 uses plain bearings on the crank so the oil system on that engine is high pressure. If the oil light goes off with a simple oil change on the KZ550 then something is wrong with the bikes oiling system such as bearing clearances are to loose or the oil pump is worn out. Changing from 10/30 weight to 20/50 shouldn't have any effect on oil pressure if the engine is healthy.

Agreed. 10w40 is about the heaviest the 550 would want.

20/50, maybe if your in hot weather all the time.

Also there is a nice performance increase going from 20/50 to 10/40. I noticed it myself, on a fresh 20k mile 81 550 GPz...but maybe an old clanky motor I'd go for 20/50.

The oil pressure is regulated by spring tension which bleeds off excess pressure at high rpms, most oil pressure guages are just reading what the pressure regulator is set at, about 65 psi on these 550's IIRC so at idling rpm is the best test for a true reading of crank bearings and oil pump.

Early 550's were oil pressure, later ones oil level.

Tyrell Corp wrote: Also there is a nice performance increase going from 20/50 to 10/40. I noticed it myself, on a fresh 20k mile 81 550 GPz...but maybe an old clanky motor I'd go for 20/50.

I had the same experience. I put some 20w50 into my clanky old Gpz550, and it was a dog. I went back to 10w40 to regain the power, and just live with the clankiness.

Sounds to me like a pressure gauge is call for.