Help! flickering oil-lamp!

[ofstone]

 Today I  had the problem that during a ride early in the morning the ride after 30 km,s of highway at 120 KM/hour 6500 rpm the oil light started flickering, first a small flickering once every 15 seconds and it started to flicker more and burning longer so I emidiately pulled the clutch stopped the bike and the light stayed on for 3 seconds when idling and then went of. I stopped the bike to check the oil level, and after 1 minute the amount of oil in the window was ok little more than half between low and high. I started her back up and the light did not burn anymore. On the way back tonight I was riding 110 KM/hour 6000 rpm and no oil light visible anymore. I think it has to do with the 10W40 oil, so I will replace the oil for 20W/50 oil. Or maybe I overfilled the bike, as I looked after an one hour the oil lever was a little above max. There was about 100ml to much of oil in it, but I can not understand that little to much oil causes the oil to foam by the rotating crankshaft or the balancer shaft. I checked the wiring from the oil light to the oil sensor and it looked ok. I do not suspect the oil sensor because they do not fail a lot.
And the lamp looks ok during the start.
What is Causing this problem. It dos not look like a typical vision problem to me and the bike only has 23000 KM on it.

[Walt_M.]

My first thought was wiring but you say you checked that. I reread your last post, 'she's running but has a cold' and you said you had found oil in the airbox, that is one of the more direct results of overfilling. Also, I don't believe the loss of pressure would be due to overfilling and foaming, I think that is one of the benefits of synthetic. Which pretty much leaves you with the 10W40 oil, although I would not expect that to be a problem unless the ampient temp is very warm. Your engine does not have enough KM on it to have 'wear'. Is the oil filter installed correctly and oil seals in place? Just guessing so far.

[Lucky]

I haven't re-read any of your posts, but I've been told if you've had the clutch case cover  (right side) off you MUST replace the crankshaft oil seal, or you'll lose oil pressure.
--Lucky

[ofstone]

Ok guys this is what happened after i did again a high speed ride of 120 KM/hour (maximum driving speed in the netherlands so almost everybody is riding at this speed exept for busses and trucks, they have a speed limit of 80 km/h) with 20W50 oil.(not overfilled, oil-level was right above the midddle between the max and min stripes) temp tonight whas about the same as this morning 14 dergrees celcius.

I first gently ride the bike warm in my town and than started on a ride on the highway. I first was riding about 15 km at 120 km/hour and then took the exit and drived back in the oposite direction for 20 KM. The first 10 km i was riding 140 km/hour (i know, that is to fast bot the road was totally empty!) and the rest at 120 KM/hour.
At the end i was riding in the tunnel under a cannel and pulled the gas wide open. (sounds verry nice in a tunnel) I took the exit about 1 km behind the tunnel and took the highway back to the exit where i started. In the tunnel it happened:driving 120 KM/hour suddenly the warning light started to flickker again while driving out the tunnel, so i amediately released the gas, and pulled the clutch. The light now was burning below 3000 rpm and flikkering above. This situation stayed like this for 15 secs (i m not sure time seems to stop when this happens) and than during the engine was idling the light went of, and never came on again for the next of the 3 KMs ride at about 80 km/h. AT the exit i accelerated again back to 120 and nothing happened.

To me it looks like something is failing due to overpressure or overheating, and 'resets' itself after a while. During this the temp of the engine never got over the middle, exept on the road from the highway back to my house. There the needle was going a bit over the half. but nothing happened there although i acelerated there to about 9000 rpms.

it does not look like there is something missing but failing due some kind of stress.

I really dont have a clou about what is going on. It looks like the oil presure is really dropping, but why after a long time?

I am now looking to the schematics in the manual, and the only thing i am thinking of is something like a seal popping and than popping back, but why at about the same distance as this morning? It is clear that the oil has nothing to do with all this.

And to make things worse, after i stopt to turn into the driveway to my house, i released the clutch to fast and the engine stalled. So i started it again and after turning one crankshaft turn the starter sounded like running, but was not turning the engine. After i push started it and stopped it again the electrical starter did work back.

I am afraid that i really need to open the side covers and take a look in there.

By the way, none of the covers look like they have ever been opened before

[Lucky]

First, the electronics in these things have never been the best, and now their 20 + years old...

you might want to think about picking up an oil guage kit, the kind with the nylon tube that reads actual pressure, and using that instead.  I have one on mine, and when the bike is really hot i've seen it drop down as low as 12psi, normally it's around 55 psi when idling cold.

--Lucky

[ArrrGeee]

I tend to agree with Lucky, don't panic, put a guage on the
engine to test it, then pick up a new oil sender
it's likely that you just have a bad sending unit.
if you had oil pressure problems you'd know it by now.
the little nippondenso senders are cheap and do fail.
I've easily replaced quite a few of them over the years.
I will qualify the cheap statement and say that they used to
be about 7 or 8 bucks. What the Yamaha dealer gets for them is anybody's guess...

-Ron

[rick_nowak]

Ditto Ron on the oil pressure senders being cheaply made and failing.  i have run lots of volkswagons water cooled over the years and have replaced many of these little buggers.  with a new one the oil light stops coming on and the buzzer goes away.  cheap fix.,  it happens

[ofstone]

Yes it could be possible that the oilswitch is bad, becouse it is leaking a verry small amount of oil from the screw wich holds the electrical wire.

I dont have a pressure test set or know someplace where i can borrow it. Whe have sensors at my work, but i can only use it with water or air, not allowed to connect it to the oil.
I Have ordered a new oil pressure sensor available tomorrow, but today it started to rain and thunderstorms a lot, so no testriding for at lest tomorrow, dont know what the weather is in the weekend.

I have e theory about what happens during the failing sensor.
I presume it has a membrane, and what if there is a small crack in the membrane. Than a small amount of oil would leak behind the membrane, and slowly would equalize the pressure on both sides of the membrane causing the switch to come active. After running at idle the oil flows back thru the crack, and outside the sensor, switching off the light. and starts filling up again when the oil pressure rises again.

I will do some testing on the sensor if possible tonight.

I really do hope it is the sensor causing problems

[ofstone]

I have removed the oil sensor, and temporarely replaced it by my old broken temperature sensor, witch seems to have the same thread as the oilsensor, to hold the oil in.

I cleaned the sensor, and there was not a lot of oil in in, but there definately was some oil in there.

I cleaned the outside, and oil side of the sensor, and managed to attach the sensor to a handpump with a fuel hose and connected a multimeter to the sensor housing and screw.
I measured the sensor gives contact upto 0,35 kg/m2 and gives back contact below 0,3 kg/m2 (same as BAR). This looks just as the manual describes the sensor characteristics.
I now have it pressurized upto 3 bars, and wil let it stay like this for about 1 hour to se if the sensor gives contact.
It looks like the sensor is ok and airtight, but the only difference is that the real oil pressure would be a bit pulsating, and the oil sensor wil be much hotter, so that could make a difference.

Has anybody has expierienced the same (on a bike or car)as i have, i mean the oil pressure looks right, but after a while the sensor gives bad values like i described?
I know Ron said he has experienced this before, but when it fails, it looks like the sensor should give false readings just after the start also, and not while riding after 30 KM,s.

[ofstone]

Today went to the shop for my new oil pressure sensor, and the new one has is swithing off above 0.1 bar while the original one is at 0.3 bars. They say they ordered the 0.3 bar for my bike, but yamaha says it is replaced by the 0.1 one as a modification!???  I wonder why.....

Before i mounted the new one i decided to do some tests and first opened the 'old' 'sensor, and found nothing more than a little bit of oil a spring and nothing strange inside.
After that i managed to mount a manometer on the oil sensor place, and measured the oil pressure after i ride the oil to about a temp of 70 degrees celcius.
AT idle 1500rpm the oil pressure was about 10 PSI and at 6000 rpm 30 PSI
the idle pressure looks ok, but the pressure at 6000 rpm looks a bit low to me. And this is with 20W50 oil at 70 degrees celcius. i wonder what happens when the oil temp is about 95 degrees celcius.

i did not drive the bike with the manometer, but monday, or tuesday, a collegue of mine will bring me an automotive electrical oil pressure sensor so i can actually measure the pressure while riding.

Also the starter cluch seems not to work good anymore since i changed the oil to 20W50. I wonder if it as a coincedence or due the thicker oil. It looks like everything is spinning around, but not turning the engine. After a push start, it turns a couple of turns, and then the bike starts, or the cluth is freewheeling without turning the crankshaft