oil overfill

7695 Views 18 Replies 9 Participants Last post by Strider, Mar 30, 2015

Tonysoup

Discussion Starter · Mar 20, 2015

Hey guys, I put some oil in my bike while i had it on the stand. i realised after a ride that it was too high, i mast have needed to fill it on the ground. big rookie mistake!

I did about 100ks on it before i realised the level was too high. maybe half a cup to a cup too much oil.

just wondering what are the consequences and what damage could i have caused or maybe already started ?

cheers!

1 - 19 of 19 Posts

Ey3l45h

· #2 · Mar 21, 2015

When you say "on the stand" does that mean vertical on paddock stands and relatively level?

How do you know you put in too much?

As far as possible damage done, someone smarter will have to answer that, but my gut says become very certain if it is indeed over filled then remove oil until it is within spec.

Personally I have found that measuring the oil as it goes in and comes out helps a lot.(one of my bikes is a single cylinder and drinks a bit of oil so I track it. ) Worst case drain it then put the correct amount back in.

Wait for someone smarter on potential damage.

Please correct me if I am mistaken on my gut reaction.

Ey3

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messi4

· #3 · Mar 21, 2015

Was the top of the oil still visible in the sight glass?

A cup of extra oil probably won't do anything harmful in such a short distance. I wouldn't recommend it, but I think its safe to say it will be just fine.

Now if it was grossly overfilled, I would be worried

RedAndBlack

· #4 · Mar 21, 2015

I wouldn't worry about it for just that little bit of riding.

I think I remember reading When you overfill an engine with oil, the moving engine parts make contact with the standing oil in the pan and create bubbles which prevent the oil from moving around the engine or something like that.

Either way, I really wouldn't be worried about it as long as you correct it.

messi4

· #5 · Mar 21, 2015

RedAndBlack said:
I wouldn't worry about it for just that little bit of riding.

I think I remember reading When you overfill an engine with oil, the moving engine parts make contact with the standing oil in the pan and create bubbles which prevent the oil from moving around the engine or something like that.

Either way, I really wouldn't be worried about it as long as you correct it.

Indeed. Creates basically a foam pit that restricts flow. However all engines have a little bit of a buffer on the fill line.

I have seen uneducated people( 3 different people actually) fill their car engine with oil all the way to the fill cap.. They didn't make it very far before realising something is horribly wrong.. But if they are smart(?) Enough to stop right away, have saved themselves from massive repair bills. (I wonder why it would stall right away and smell like burning? I just put oil in!)

Also observed a person removing their rad cap from their car to "remove the excess pressure that is causing coolant to pour onto the floor and run under the seat" instead of fixing their heater core. But that's for another day..

riverszzr

· #6 · Mar 21, 2015

1/2 cup is what 4 ounces

It would still be in the window at that amount extra

Check your oil level;

front and rear tires on the ground--flat ground---bike stood up and level side to side---look at the window on the right side of the bike.

There is a low line and a full line, I usually set bikes right in the middle of that, but as long as you can see oil in the window atleast to the low line and atleast some amount of air bubble at the top you will be fine for short term, possibly even long term (too many variables to state factually)

So if you are only 4 ounces or even 8 ounces too much, you would be fine.

Tonysoup

Discussion Starter · #7 · Mar 21, 2015

thanks guys, yeah no bubbles and just above the sight glass. give fixed the level with both wheels on the ground, bike level.

lol the radiator story... yeah theres always someone.

i just got the bike so naturally im in the pedantic stage haha

thanks for your help!

Tonysoup

Discussion Starter · #8 · Mar 21, 2015

thanks guys, yeah no bubbles and just above the sight glass. give fixed the level with both wheels on the ground, bike level.

lol the radiator story... yeah theres always someone.

i just got the bike so naturally im in the pedantic stage haha

thanks for your help!

RJ2112

· #9 · Mar 21, 2015

Overfilling a motor with oil will indeed create a froth of oil that does not pump well.... that can lead to oil starvation and a seized bearing...... this is not the greatest risk resulting from too much oil.

If the cases contain too much oil, it will eventually get pulled through the EGR valve and will be dumped into the air box, behind the filter. This always happens to some small degree; the harder you run the motor at the greatest lean angles possible, the more you will see it. That's why there is that litlle bottle hanging off the lowest point of the air box, so you can see it and keep it out of the engine. It's only meant to catch a tiny amount of effectively condensate.

If you are seriously over filled -- and this is greater than a quart over the upper limit -- you are at risk of causing hydraulic lock. That would be bad. Catastrophically bad.

When the EGR (exhasut gass recirculation) valve dumps the engine case gasses back into the air box, so the engine can burn off the oil fog rather than vent it to the atmosphere, that's a good thing for people, kittens, whales, etc. The fog occurs because the rings cannot have a perfect seal to the cylinder walls.... it's unavoidable.

When that same valve sucks up liquid oil and pumps that into the intake -- liquids do not compress. If the volume of liquid is high enough, it will stop the piston from moving up to complete the compression stroke. A 13:1 4 cylinder 600 cc motor has a very small amount of volume above the pistons at top dead center.

600/4 = 150 (volume of one cylinder at bottom dead center)
150/13 = 11.5 cc (volume of one cylinder at top dead center)

Not only do you have the fuel/air mixture in that volume... there is the tip of the spark plug, and those pesky valves that are SUPPOSED to get out of the way before the piston gets there.... extra drag, even higher than expected compression, those are bad things as well.

If you do manage to get 11 + cc of oil into a cylinder... bent valves, bent rods, damaged crankshafts, totalled motors......... usually this involves a big puff of smoke, a 'bang' and quite possibly a locked rear wheel -- or a huge amount of oil under a locked wheel.

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Reactions: 3

RedAndBlack

· #10 · Mar 21, 2015

Very good write up and informative!!!! ^^^^^

riverszzr

· #11 · Mar 21, 2015

You guys do realize modern day sportbikes have the cranks and the transmissions very high, way above the oil level. About the closest thing to being able to froth up the oil is the bottom of the clutch basket in most cases.

And not that I am a fan of stunting or anything but those run an extra quart or two of oil in their bikes as a matter of practicality and I have a few of those guys that ride them around on the street that way to get to their favorite stunting grounds and besides the occasional oil seal blow out, they seem to suffer little from the oil being way above the top fill line...

Just for the devils advocate point of view.......

I still highly recommend to stay between the top and bottom line on the sight glass!

Reactions: 1

RJ2112

· #12 · Mar 21, 2015

My point of reference is to car engines more than modern sportbikes.... the lean angles make it pretty obvious the oil levels would have to a very wide margin of safety in a bike motor that can go vertical in a wheelie, as well as very nearly laying on either side, and high gee -- having the oil pickup where it would never be pulling air is a (IMHO) very impressive bit of engineering.

Ebster1085

· #13 · Mar 21, 2015

Probably not a big deal.

That being said, there are max and min lines for a reason.

When the oil is overfilled it can get churned up by the spinning crank and can become frothy. This reduces its ability to properly lubricate the engine components.

I am hoping by now you drained out some of the oil to get it to the proper level?

Norcalmob

· #14 · Mar 30, 2015

So what is the correct fill line? top bottom or in the middle.I have a 07 zx6r and currently it's right at the top line maybe a tad above is that bad or nah?

RJ2112

· #15 · Mar 30, 2015

Norcalmob said:
So what is the correct fill line? top bottom or in the middle.I have a 07 zx6r and currently it's right at the top line maybe a tad above is that bad or nah?

I aim for the top line..... that way it's easy to see any loss between changes.

Tonysoup

Discussion Starter · #16 · Mar 30, 2015

thanks guys

RJ2112 fantastic, cheers mate

Norcalmob

· #17 · Mar 30, 2015

And that's after it's been running? cuz if I let it sit it will be way above the top line but after I let it run its about even?

riverszzr

· #18 · Mar 30, 2015

NO--not while running, or even immediately after it has been running.
Give it atleast 10 minutes of sitting still to drain back down- then check level, and not on a sidestand or rear stand either

wheels flat on the level ground and bike tipped up level side to side

Then realistically anywhere at or between the two lines is fine, I set them near the top line though~ just for ref

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Strider

· #19 · Mar 30, 2015

RJ2112 said:
My point of reference is to car engines more than modern sportbikes.... the lean angles make it pretty obvious the oil levels would have to a very wide margin of safety in a bike motor that can go vertical in a wheelie, as well as very nearly laying on either side, and high gee -- having the oil pickup where it would never be pulling air is a (IMHO) very impressive bit of engineering.

Even leaning way over in a corner, because of the G forces, the oil will still stay pretty much in the bottom of the pan like it does when the bike it upright.

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