76 R90/6 - oil light at idle/low rpm, no oil light while riding

[20774]

Probably best to replace the switch just so you know it's good. I suppose there would be a couple of ways to check things:

- put an ohmeter across the terminals on the switch and start the bike. At some point, the resistance between the terminals should go to zero to indicate the switch is closed.

- if you're replacing the switch anyway, take the old one and and again connect the terminals with a meter. Then with an appropriate metal drift, push into the orifice to close the contacts...see that the meter shows zero resistance.

But if you want to know if the bike is creating the right level of oil pressure:

- plug in the appropriate pressure tester in place of the existing switch to confirm that you are getting the spec pressure to the switch.

 

[concernedparent]

OK SO. Replaced the sensor with the new sensor from boxer2valve. (not sure why the photo is upside down it's right side up when i open the file on my desktop) the old sensor was pretty crudded up, and was very moist and moistened the connection tab (female end back to wiring).



turn the key (not start bike) the light comes on for the oil light, like normal. start the bike light goes out. warm the bike up no oil light. ride around in stop and go traffic in queens for 20 minutes no oil light. i did notice that the motor felt a little hot, but it also was pretty hot out yesterday and i was also riding in baggy pants that allowed a lot of airflow from the heads and was also wearing thin sneakers, something i normally don't do.

i didn't touch the oil/filter yet, but it would it better advised to ride a little bit and see if the problem comes back before changing that? or is that better peace of mind alleviating other possible issues?

 

[20774]

So, you changed oil less than 1K miles ago? How long ago was that? If the oil light doesn't come on anymore and you still have some time to go before needing to change the filter/oil (say by mileage or by time), then I'd wait until a normal filter change.

 

[concernedparent]

So, you changed oil less than 1K miles ago? How long ago was that? If the oil light doesn't come on anymore and you still have some time to go before needing to change the filter/oil (say by mileage or by time), then I'd wait until a normal filter change.

only a few months back, i'd say april 2021 is when i last changed it. i have not changed the filter since i got the bike however, which was 2 years ago. should i be ok until my next oil change, and then at that point definitely do the filter?

 

[20774]

Well, that's interesting. Personally, I would want to know that the filter was good and doing its job. The manual suggests changing the oil and filter at 5K miles (from memory). I tend to change more by time, maybe every 18 months or so, not even close to the 5K miles. I think I've read the suggestion that the filter is a bit more important than the oil. I think their idea was change the filter more often than the oil...in other words, change the oil every other filter change. If the filter is doing its job, it should be pulling out the bad stuff. That doesn't really speak to water build up, and combustion products that tend to crop up with limited and/or city riding.

So, if it were me, I'd change the filter and since you just did the oil and top off with more oil as needed. You could lean your bike to the left to minimize how much oil flows out of the housing.

Something else to consider once you've changed the filter. It would be best if you were to "prime" the filter. That is, crank on the starter until you see the oil pressure light go out. To do this, I usually carefully drop my float bowls so the engine can't start.

 

[stevenrankin]

Filter Change

If you have doubts about the filter, change it. The cost of a filter is cheap compared to an engine rebuild. As Kurt says, lean the bike a little bit to the left to cut down on the oil lost. Even. if you don't lean the bike, there will be very little oil lost at all.

I'm glad your light problem is fixed but, go a bit further and make sure the filter is good. St.

 

[RPGR90s]

Probably best to replace the switch just so you know it's good. I suppose there would be a couple of ways to check things:

- put an ohmeter across the terminals on the switch and start the bike. At some point, the resistance between the terminals should go to zero to indicate the switch is closed.

- if you're replacing the switch anyway, take the old one and and again connect the terminals with a meter. Then with an appropriate metal drift, push into the orifice to close the contacts...see that the meter shows zero resistance.

But if you want to know if the bike is creating the right level of oil pressure:

- plug in the appropriate pressure tester in place of the existing switch to confirm that you are getting the spec pressure to the switch.

With a running bike, wouldn't the switch show an open circuit, since the oil light would be off? My understanding is that the oil pressure switch is normally closed (light on) until the engine starts, develops pressure to then open the switch (light out). Inserting a drift into a switch to push on the orifice would open the switch, no?
Unless I have it totally backwards....

 

[20774]

With a running bike, wouldn't the switch show an open circuit, since the oil light would be off? My understanding is that the oil pressure switch is normally closed (light on) until the engine starts, develops pressure to then open the switch (light out). Inserting a drift into a switch to push on the orifice would open the switch, no?
Unless I have it totally backwards....

I might be the one that is bass ackwards! Either way, the switch should work to change the circuit.

Update...saw a post by Snowbum on the Airheads list and he said that the switch opens around 5psi or so. So, sounds like it is normally closed. I was thinking of the brake master cylinder switch and the process Brook went through to verify operation. But that switch is normally open and sends power to the brake lights when the switch closes. Different animal.

 

[RPGR90s]

I might be the one that is bass ackwards! Either way, the switch should work to change the circuit.

Update...saw a post by Snowbum on the Airheads list and he said that the switch opens around 5psi or so. So, sounds like it is normally closed. I was thinking of the brake master cylinder switch and the process Brook went through to verify operation. But that switch is normally open and sends power to the brake lights when the switch closes. Different animal.

That's why this is such a good forum. Logical discussions so we can all learn.

Thank you sir

 

[tsconver]

Sounds like it is fixed, but anytime I have a low oil pressure warning I check the pressure with a manual gauge to confirm the real pressure then go from there.

 

[concernedparent]

so just to close the loop on this. finally got around to swapping out that filter yesterday (have not really been riding too much due to work, life, etc.). the old filter was a total mess to get out, would come about halfway out and then hung up. i read in other threads it is possible the previous owner installed an oil-cooler specific filter that could grab onto that center shaft. eventually got it out. and all was clean inside. notable was the outer o-ring on the old filter had a small tear in it, which i would suspect would have something to do with an oil pressure drop.

installed new filter (hinged type) that comes with the o-rings on the filter already, slapped the whole thing back together and put the outer cover on with the new gasket. my question is: the kit came with the "$2,000 o-ring" as well as some shims and a drain plug seal. just to be sure, that $2,000 o-ring isn't needed on a 76 r90/6, correct? there wasn't one in there when i took the old assembly apart. and my drain plug washer that was in there was in fine shape so i left it as is. (link to kit i purchased -> https://www.boxer2valve.com/oil-filter-kit-wo-cooler-ox37d.html)

in any case, put 2.25L of liqui-moly in and fired it up and she sounded happy. i "primed" the filter by cranking on the starter a few times before letting the bike run, and when the bike began idle the oil light remained on for about a second and then it went out. rode around for 10 minutes or so and the oil light does not come back on.

woohoo? i think so, but if i'm missing something critical here with those extra parts that were included in the filter kit let me know.

 

[20774]

my question is: the kit came with the "$2,000 o-ring" as well as some shims and a drain plug seal. just to be sure, that $2,000 o-ring isn't needed on a 76 r90/6, correct? there wasn't one in there when i took the old assembly apart. and my drain plug washer that was in there was in fine shape so i left it as is.

You are correct...only the /7 bikes and beyond would need the white o-ring and thin metal shim. The gasket may or may not be needed on the /7-on bikes.

You would need the filter and the black gasket...it's your choice on the drain plug washer, but I would have replaced it. But now you have a spare for next time!! I've never changed the filter on a /6 bike so don't know what goes on inside the cover. I know there is another cover with a nut/bolt on it. Not sure if the inner cover has any o-rings on it...maybe it just seals against the outer o-ring that is secured to the hinged filter.