Repercussions? - overfill oil

[Kukku]

Hi All,

Interested to know ... apart from wasting money and a mess in the airbox and air filter, what are the repercussions of overfilling with oil?

Thanks in advance!

Chris

[turboguzzi]

if it drained overnight into the cases, then oily deposits on plug and piston (change plug, rest will clear with riding), and worse could be a blown out oil seal at the gearbox output shaft, but it does have a retaining plate to prevent it in.... in short, likely no repercussions, just dont do it again!

[Two wheels good]

It depends .. what type of bike, dry/wet sump and how much overfilled. Maybe high crankcase pressure, blown seals, leaking gaskets, burning oil.
You can always save what you remove for later use!
How far do you have to tilt the bike to see the level in the sight-glass? Horizontal?

[turboguzzi]

Originally Posted by Two wheels good

It depends .. what type of bike, dry/wet sump and how much overfilled. Maybe high crankcase pressure, blown seals, leaking gaskets, burning oil.
You can always save what you remove for later use!
How far do you have to tilt the bike to see the level in the sight-glass? Horizontal?

We are in the xt600 forum.... oh well...

[Tomkat]

On some wet sump engines, if you overfill the oil the crank can dip into it, aerating the oil and starving the pump.

[Kukku]

Thank you all for the input ... this mainly referred to a 1999 XT600, so dry sump. It's good that you also included response about wet sump engine.

Mechanic didn't look up the manual and so filled with almost 4 Liters of oil. What seems strange to me is the fact that I didn't see any exhaust smoking ... I would have thought that excessive oil on piston would smoke badly.

Regards,
C

[Two wheels good]

Originally Posted by turboguzzi

We are in the xt600 forum.... oh well...

No, the Yamaha forum.

[Two wheels good]

~4L is a lot; more than 1L excess? I'd drain it to the correct level.
Wouldn't the mechanic correct the error? (Maybe you're on the road)

[Tomkat]

Originally Posted by Kukku

dry sump.....

Mechanic didn't look up the manual and so filled with almost 4 Liters of oil. What seems strange to me is the fact that I didn't see any exhaust smoking ... I would have thought that excessive oil on piston would smoke badly.

Regards,
C

Why would you see smoking with excess oil on a dry sump engine? The amount in the crankcase will be constant and the excess oil will be pumped up into the oil tank, probably causing it to overflow, though there may be a venting system that routes it through to the airbox. saturating your filter. Or it may just vent overboard onto the road if that's how the tank is set up.

[Kukku]

Well I guess my bike doesn't drain into the cases at night ... that is when potentially it will smoke if I understood correctly ...

if it drained overnight into the cases, then oily deposits on plug and piston

[turboguzzi]

Originally Posted by Kukku

Well I guess my bike doesn't drain into the cases at night ... that is when potentially it will smoke if I understood correctly ...

Indeed, in a perfect world, dry sump should stay dry until end of times, in reality, most anti drain check valves leak a bit so after some time (varies from days to weeks) oil finds its way down.


Thats the reason you check oil level in xt's only after running it for a few minutes, to bring back to tank the oil that's in the engine

[Kukku]

Indeed, in a perfect world, dry sump should stay dry until end of times, in reality, most anti drain check valves leak a bit so after some time (varies from days to weeks) oil finds its way down.

Thank you, that super explains everything.

Regards,
Chris