Oil light stays on .....

[nevada72]

Edit - File this one under the "never mind" category. I was looking at the wrong light.

I have a recently acquired a "ran when parked 3 years ago" 1983 R100RT. The bike looks fairly unmolested with no obvious buffoonery so often found on bikes of this vintage - i.e. everything looks oem. I did the basics to do a first start to evaluate - fresh gas, check carb bowls to gauge neglect (they were dry), check oil (it's so-so), new plugs, new air filter (old one looked like it was 100 years old), charged battery. It turns over fine, but the right carb leaks like a sieve (replaced bowl gasket - no help). Guessing the float doesn't, among other things. But even so, I figured it would at least start with a full bowl and the gas shut off. Not so much. It gets spark, it's getting air, so I figure carbs need to be rebuilt.

But that's not my primary concern. In reading up on the oil change situation, I learned of the oil cooler/filter change nightmare. Somewhere along the line I read when changing the oil and filter one should crank the motor with the plugs out/gas off in order to pump oil into the filter. I thought I read that after cranking a short while the oil light is supposed to go off. Mine doesn't. Is this a problem?

Btw - this is not my 1st post. I originally joined in 2008. My membership expired and I didn't renew until recently. I guess my old posts and count have evaporated.

[20774]

Welcome back! What was your previous username? Maybe it's still out there and you can be connected back to it.

That's what I've been doing when I've changed my oil filter on the /7. I don't pull the plugs but instead, drop the float bowls with the gas off. I hit the starter and wait for the oil light to go out. The last time I did it, I'll admit that the amount of time for that to happen was too long!! But eventually it did go out.

So I'm assuming you changed the filter this time around. How did that go? What parts did you change? Have you had a chance to measure the depth that the oil canister sits below the surface of the engine? It's important to know that so you can assemble the proper amount of shims and paper gasket (if necessary). If it's not right, you could not be building the proper pressure.

The oil sending unit comes on at a very low oil pressure, around 5 psi. So, if there's any kind of pressure, the light should go out. Probably the lowest the oil pressure is under less than ideal situations is around 15 psi, so for it to be in the 5 psi range, something isn't right.

You're kind of in a tricky situation. Make sure that the oil filter components are right. If they are, then you might need to consider adapting a pressure measuring device to the replace the oil sending unit. Then you can crank the engine and see what the reading is. Cold pressures can be above 60-70 psi. I'd be less inclined to start the bike and see if under normal running situations, the light will go out. I don't know what the time frame is for ruining the engine with low oil pressure, but it's probably not long.

Let us know what you find out about the filter components.

[nevada72]

Thanks for the welcome and info Kurt. My name is the same now as then. I logged on and renewed with my old info, so I'm not sure why it reset. Maybe just too long of a period between renewal. I'll be interested to see if my member number is the same.

I didn't touch anything oil related mainly because I didn't want to mess with the filter until I have a complete understanding as to replacement. I also wanted to warm up the current oil before draining. The oil itself looks marginal - not horrible - not great. But it still felt and smelled ok. I've seen far worse. So I was willing to risk a cold start to warm up the oil to drain it. It was at that point that I noticed that the oil light stays on while cranking. My hope was/is that it had to do with sitting so long. Now I have my doubts.

Honestly, I didn't pay all that much for the bike. I hate to toss a bunch more at it only to discover the motor is toast. On the other hand, I don't want to just write off a potentially excellent bike.

I may do as you suggest and check out the oil filter and see how it was installed. That might give me a heads up. I have all the filter parts, so I have little to lose. I just hate to drain cold oil. Oh well.

[BlueWaterCooled]

Thanks for the welcome and info Kurt. My name is the same now as then. I logged on and renewed with my old info, so I'm not sure why it reset. Maybe just too long of a period between renewal. I'll be interested to see if my member number is the same.
…

[digression]
I renewed after an absence of many, many years, maybe 10, maybe 20, I don't remember. I still have my original number, 2607, but my join date is 2017. Makes me wonder if there is anyone still around with a lower member number.
[/digression]

[SCBuckeye]

Mine did that after I had trailered it down to SC from Ohio. I had to just remove the connector wires to the sending unit and clean them out and reconnect. Worked. Could also be a bad sending unit.

[nevada72]

[digression]
I renewed after an absence of many, many years, maybe 10, maybe 20, I don't remember. I still have my original number, 2607, but my join date is 2017. Makes me wonder if there is anyone still around with a lower member number.
[/digression]

Yeah, I have a really low number too. Something close to yours except it maybe 3 zeros after it. I think I originally joined in 2007, so I was one after many by that point.

Mine did that after I had trailered it down to SC from Ohio. I had to just remove the connector wires to the sending unit and clean them out and reconnect. Worked. Could also be a bad sending unit.

Thanks! I'll give that a shot.

[m_stock10506]

I hate to throw this question out there, but are you sure it's the oil light? When you turn on the key, you should have three lights, Neutral, Oil and Gen. When you turn the starter motor, only the Oil light should go out until the motor fires and you get the RPM above 2K, then the Gen light should go out. Sorry, if this is too elementary, but sometimes it gets missed.

[nevada72]

I hate to throw this question out there, but are you sure it's the oil light? When you turn on the key, you should have three lights, Neutral, Oil and Gen. When you turn the starter motor, only the Oil light should go out until the motor fires and you get the RPM above 2K, then the Gen light should go out. Sorry, if this is too elementary, but sometimes it gets missed.

Great News! I'm an idiot! You are 100% correct - I was looking at the wrong light. I just went out to double check based on your words and low and behold - it turns off after a very short interval.

This is a HUGE relief!

Thank you all so much for the feedback. And I am happy to serve as the most recent "cautionary tale" of the guy who didn't understand all the blinky lighty things.

[lmo1131]

umm mm ... so what light were you looking at that didn't go out?

[Friedle]

umm mm ... so what light were you looking at that didn't go out?

Neutral ??

Friedle

[nevada72]

umm mm ... so what light were you looking at that didn't go out?

Alternator light. It's red like the oil light. Neutral is green so I was familiar.

[James.A]

I'm glad this was all figured out. That's what we do here. If you are not already a member, please consider joining the Airheads Beemer Club. The Wisconsin Airmarshal is a guy named Randy Boris, MANICMECHANIC on this forum. He is a wealth of knowledge and moonlights in an independent shop in Manitowwoc. Randy is one of my closest friends.

[MANICMECHANIC]

Drop a line sometime. Whereabouts are you located?

[nevada72]

Drop a line sometime. Whereabouts are you located?

Greetings! I'm in Lake Country. Pewaukee basically.