1982 GS650G Losing oil.

[Guest]

I'm looking to track down the cause of oil loss.

Oil light came on the other day, I topped the bike up with enough to turn the oil light off (about half a cup), but it was in again a few minutes later. (I check the electrical connection to the oil sensor and it's a good connection).

Plan includes a good look at the piston rings and replacement of the valve seals. Wasn't going to touch valve guides. (Bike has done 40k miles).

There isn't huge clouds of blue smoke out the back, so I was thinking it would be the valve seals. Good hypothesis?

Any other places worth a look? Cylinder head gasket perhaps?

Cheers guys,

Oliver.

[tom203]

How about putting bike on centerstand, filling oil to "HI"mark in window and skip the half a cup stuff. As soon as engine runs, lots of oil gets sent to valve area and can stay there for a long time after engine is shut down. Do not run this thing if oil light comes on-it needs plenty of oil pressure to keep its plain bearings happy.

[Oliverstrother]

Before I tear it down, I think I'll fill it to the correct level and see how long it takes in normal running time to get to a problem (oil light on).

It has not been run with the oil light on, the bike isn't on the road yet. It's still in testing before it's taken to the streets.

[tom203]

Before I tear it down, I think I'll fill it to the correct level and see how long it takes in normal running time to get to a problem (oil light on).

You'll likely have to wait a long time (especially just in "testing" stage). Mine runs 2000+ miles with no added oil at all.

[barnbiketom]

make sure it is LOOSING oil, and not just an idiot lite problem...

[tkent02]

Don't frack around with oil levels. Check it properly in the window, keep it at the right level, check it before every ride. It only takes a quick glance. Figure out how much oil it's using. With only 40,000 miles it shouldn't be using any oil, unless it's been abused like running it without any. Once you find out how much it uses figure out what you need to do.

If the oil light is coming on because of low oil quantity, it's about three quarts low and has already done damage. It's an oil pressure light, not an oil quantity light.

If it's coming on because of an oil pump problem, it's doing damage no matter how full it is. Putting in more won't help.

If it's coming on because of an idiot light problem, putting in more oil is doing damage.

Too much oil is worse than running a little low.

The light could also be coming on because the crankcase is full of gasoline, how well is your petcock working?

[Oliverstrother]

Great info guys

When I rebuilt it, I changed the oil and filled it to the correct level. It's not been ridden anywhere, but the light has come on following a few weeks of testing carb set ups.

No idea of the bikes history, but it appears like it's been messed with (haven't they all?)

What's the idiot light reference to? People not checking the oil level regularly? Appreciate it's a oil pressure light. Adding a little oil appears to provide more oil pressure. So maybe it's a level thing?

How could gasoline in the case (from petcock I assume),make the low oil pressure light come on?

[tom203]

"....So maybe it's a level thing?"

Note its location - in vicinity of oil pump (the gizmo that makes pressure) -it just senses pressure.Probably 8 psi of pressure opens the circuit to ground (mine goes out asap if I crank it without starting). I recall normal operating pressure is in range of 40 psi , so light should stay out even at idle. You might have defective sender- my home generator is on its third sender in maybe 600 hours usage. I blame it on the Chinese supplier!

[tkent02]

How could gasoline in the case (from petcock I assume),make the low oil pressure light come on?

Oil is thick, very high viscosity.

Gasoline is thinner than water. Put enough gasoline in the oil and it becomes too thin to build any oil pressure. It just oozes out through all the bearings and such as fast as the oil pump can pump it, it leaks back into the sump before any pressure builds up.

You still haven't answered the 100 dollar question, how much oil is in your engine?

Is it above or below the sight glass?

[Oliverstrother]

Will certainly be checking things and getting back to you soon. I'm in the UAE right now, and the bike is in Connecticut.

Will update early next week when I'm back.

The oil light normally does go off as soon as I crank it.

Idiot light?

[SqDancerLynn1]

YOU have a bad petcock ! When leaving it for weeks at a time the fuel drains into the crankcase thinning the oil

[Oliverstrother]

Back in ct,

Oil level was just below the F, after checking in the manor described in the maintenance manual.

Replaced the oil to the correct level. Ran it a for a while and the light came back on.

It turned out to be an intermittent electrical failure, wire pinched.

Still loosing oil, but I think it's slow, I get some smoke on start up, but it soon disappears when it warmed up.

Planning a compression check in the near future.

[tom203]

Just run it and see if smoke lessens- might be sticking rings from sitting