What does this mean?

I've been working on my KZ650 SR. Carbs, ignition. When I was finished for the day, I went to shut down the engine and I noticed the OIL light was lit up. Since I'd been working on electrical components, I thought maybe I'd grounded the sender or something. I took a look in the oil window just to assure myself that the bike has oil in it. The window shows oil up past the top, completely filling the window. I haven't added any oil lately and the last times I checked it, the level appeared normal. That makes me more nervous than the OIL light coming on. What might cause the all-filled-up oil window symptom? And could what causes that cause the oil light to come on?

Thanks

is the light on when the engine is off? if so that be normal

Good question kzwolfsr .. the light comes on when the ignition switch is in the on position. When cranking the engine, it glows steady, more or less. The neutral light and the oil light dim in tandem while the starter is drawing juice.

markc3wa wrote:

I've been working on my KZ650 SR. Carbs, ignition. When I was finished for the day, I went to shut down the engine and I noticed the OIL light was lit up. Since I'd been working on electrical components, I thought maybe I'd grounded the sender or something. I took a look in the oil window just to assure myself that the bike has oil in it. The window shows oil up past the top, completely filling the window. I haven't added any oil lately and the last times I checked it, the level appeared normal. That makes me more nervous than the OIL light coming on. What might cause the all-filled-up oil window symptom? And could what causes that cause the oil light to come on?

Thanks

Would sniff-test crankcase oil to detect any gasoline odor evidencing fuel intrusion into crankcase (a serious condition). Also physically examine the oil to see if it feels thin and diluted. If in doubt, should change oil and filter, and of course correct the problem. If this is the case, am thinking the carbs or at least one of them is going to need more work.

Good Luck!

Thanks, Patton, I'll try that tomorrow. I did have a little trouble with the number one carb (float needle valve installed upside down ... d'oh!). That was such an obvious leak I was able to figure it out quickly. Maybe not quickly enough.

While back inside the carbs, would also assure the overflow circuit is clear. (Holes in brass overflow tubes not obstructed). But even a clear overflow circuit can be overwhelmed by too much incoming fuel.

Here's what sometimes happens. Excessive fuel rises up inside carb and gets to carb throat and then flows both ways: (1) toward engine into combustion chamber then down around pistons into crankcase; (2) toward air filter where may collect at bottom of filter box and drain down through crankcase vent tube into crank case (but not with pods which just allow drainage straight to outside world).

The problem can occur whether or not the engine is running. So better practice is to turn off a manual petcock when the bike is parked. Vacuum style petcocks are of course supposed to turn off automatically when the engine stops running.

But regardless of petcock position, a properly sealing float needle/seat interface should regulate fuel level in carb floatbowl without allowing an overflow situation.

Smoothbore carb users are particularly sensitive to this problem because smoothbores don't have an overflow system. And when using an airbox, often disconnect the tube from bottom of airbox to crankcase vent and run a hose from the crankcase vent to underneath the bike.

Good Luck!

OK I think I dodged a bullet today. The oil light circuit did not appear to have a short in it. I did the sniff test and there must have been a quart of gasoline in the crankcase! That would explain the completely filled-in oil window. I drained the crankcase, replaced the filter and o-rings, refilled with fresh oil and crossed my fingers. I started the bike and the light went out, at least with cold oil in it. The task now is to figure out how the fuel got in there in the first place. I think it was mainly from forgetting to turn the petcock to ON from RES after my earlier tinkering. Maybe a float needle isn't seating completely.

Thanks for your help, I'm sure there will be more needed in days to come.

re: the petcock .. from PRI to ON, not RES to ON.

As known, it's good practice to leave a manual petcock turned off while parked. And for a properly functioning vacuum petcock to be in run position while parked (as it is then supposedly off). But this doesn't cure the problem.

Please remember -- fuel intrusion into crankcase due to incomplete seal at float-needle/seat interface can occur whether or not the engine is running. And this condition may be worsened by a clogged float-bowl overflow.

So should indeed follow-up on attaining proper sealing between the float-needle and float-seat, and meanwhile keep a close eye on the crankcase oil situation.

Once upon a time, I was lucky enough to dodge that same bullet.

Good Luck!

If you look at the carbs design and where the overflow drain is positioned relative to the intake throat into the cylinders it "appears impossible" for gas to ever get in the engine that way. Reason I say "appears" is that I call it impossible because gas has to rise 5-10mm higher than the drain and like a bathtub drain, the drain is just that, keeps level low enough to safely isolate the gas from possibly entering the engine. I could take all 4 floats completely out of any of my motorcycles, turn the gas on, watch 4 gallons of fuel flow all over the floor and zero into the engine. That being said gas has entered engines here on quite a few guys bikes, so my logic must have a flaw somewhere:P Be sure and also check out the vacuum petcock, as a leaky vacuum diaphram can also send gas straight down the vacuum line into the engine.

RonKZ650 wrote:

If you look at the carbs design and where the overflow drain is positioned relative to the intake throat into the cylinders it "appears impossible" for gas to ever get in the engine that way. Reason I say "appears" is that I call it impossible because gas has to rise 5-10mm higher than the drain and like a bathtub drain, the drain is just that, keeps level low enough to safely isolate the gas from possibly entering the engine. I could take all 4 floats completely out of any of my motorcycles, turn the gas on, watch 4 gallons of fuel flow all over the floor and zero into the engine. That being said gas has entered engines here on quite a few guys bikes, so my logic must have a flaw somewhere:P Be sure and also check out the vacuum petcock, as a leaky vacuum diaphram can also send gas straight down the vacuum line into the engine.

Have also wondered about that apparent impossibility. But thinking perhaps some carbs have freer flowing overflows than others. Or maybe there's a clog or obstruction somewhere in an overflow passageway beginning with entrance hole at top of the overflow tube inside the floatbowl and ending at tip of drain hose before exiting to the garage floor (or maybe a kink in the drain hose). And it only takes one single carb with an overflow malfunction to cause the problem. As noted, the smoothbores are particularly succeptible because they don't have an overflow system.

And thanks for the excellent reminder about checking a vacuum petcock for possibility of a leaking vacuum diaphram whereby gas could be sent straight down the vacuum line into the engine. As known, this is a reason some prefer the manual style petcock (and remembering to turn it off when parked). Actually, I enjoy being able to turn the manual petcock off before arriving home, to minimize gas remaining inside the floatbowls while parked.

Now, about that clutch pushrod adjustment . . . :laugh: