Fluctuating oil tank level

Hi,
This is my first thread so here goes.

I cant seem to get my oil level to settle in the oil tank on my 00 Mille R. I changed the oil filter and re-filled the tank up to Max level. After going for a run, the oil level in the tank rises until it fills the tank right up to the filler plug. It then seems to stay at this level. Checking it in the morning, the level drops back to near minimum.

I dropped the bike at a roundabout and the original oil cooler got damaged so I fitted a secondhand replacement which looked in very good condition. The oil level problems seemed to have started following getting the bike up and running again after the accident.

Any ideas guys??

Regards

There is a correct procedure for checking the oil level on these bikes as the Rotax engine has a dry sump and is not as per your typical japanese inline 4

If you filled the engine up with oil to the max mark on the sight tube, then there is a pretty good chance you have way over filled it with oil. Don't start the bike fella until you've determined how much oil you've put in. 3.5 to 3.75 litres is the norm from empty. From what you've said my guess is there's about a litre too much.

There are also 2 drain plugs, one on the bottom of the tank and one next to the oil filter housing. Did you undo both to let all the old engine oil out when changing the oil?

This is the correct way to check the oil level. It no good just looking at the sight tube when the engine is cold as this is not how it works

You need to ride the bike for at least 20 minutes to let the oil circulate around the engine. Then, stop somewhere safe and flat and switch off the engine. Immediately check the level in the sight tube. It should be 2/3 rds the way up and no more. Oil will be blown into the airbox if the level is any higher so you will need to check yours. I suspect it will be full of oil, so you'll need clean it all out and replace the air filter too

Hi LEGS,

Thanks for the quick reply.

I wasn't aware that there was a procedure other than looking at the sight tube...clearly I've cocked up! I simply topped up the oil level to the Max mark.

I reckon, as the oil level came right up to the underside of the filler plug, oil must surely by now have blown into the air box. Guess I'm gonna have to sort that out now.

Thanks for the info on the procedure. I've only had GSXR's before which, as you'll know simply required topping up to the correct level on the viewing window.

Hope I haven't done anything irreversible, like wrecking the air fliter.

Cheers again.

No, i suspect you should be ok. I would check your airbox for oil and see whats there. I would also drain 1/2 a litre out and go for a quick spin and check the oil level as mentioned above and go from there

Yeah its a bit of a pain the arse as its not that straight forward but you'll get used to it.

Following and oil and filter change the procedure in the book is to fill the oil tank to max, run the engine for a few minutes when you will see the oil vanish. Turn off, refill to the max mark. I always did it this way and never got oil in the airbox. Only when I was near another 3000 miles did the bike need topping up with oil. Checking the level between oil changes is as described above by the others. Strange way of doing things but just one of the Aprilias quirks! Hope that helps.

DaveRSV said:

Following and oil and filter change the procedure in the book is to fill the oil tank to max, run the engine for a few minutes when you will see the oil vanish. Turn off, refill to the max mark. I always did it this way and never got oil in the airbox. Only when I was near another 3000 miles did the bike need topping up with oil. Checking the level between oil changes is as described above by the others. Strange way of doing things but just one of the Aprilias quirks! Hope that helps.

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seriously?? wouldnt this procedure overfill the bike drastically?

Thanks for the info DaveRSV. Much appreciated. Learned my lesson this time.
Regards

178Mannyroad said:

Thanks for the info DaveRSV. Much appreciated. Learned my lesson this time.
Regards

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seriously? topping off every 3000 miles...daversv's method sounds like you would be overfilling the engine big time. Can someone explain to me otherwise. I would fill mine to the max mark and that would be that....last time i did what daversv does I ended up with oil in my airbox.

Mr_Chow said:

seriously? topping off every 3000 miles...daversv's method sounds like you would be overfilling the engine big time. Can someone explain to me otherwise. I would fill mine to the max mark and that would be that....last time i did what daversv does I ended up with oil in my airbox.

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Doesn't matter how you achieve it as long as the oil level is correct having a running or very recently run engine.

Hi guys,
Still not sure whats happening with my oil level. This is what happens:
When cold, the oil level in the tank registered on the MIN mark. Immediately I fired the bike up the level began to rise in the tube until it eventually completely filled the tank, right up to the filler plug. I ran the bike for a while till it was hot and then switched it off. The oil level remained at the high mark (right up to the filler plug) for maybe 1 hour or so whereupon it very slowly began to lower. By morning it had settled out at the MAXIMUM mark. It didn't return to its original MIN level, even though I didn't top it up! Whats going on guys? The manual doesn't seem to cater for this quirky behaviour.

By the way, I checked the air box. There isn't one as such, just a carbon fibre plate with a foam filter sat on top...and both showed no signs of oil contamination.

In the words of Tom Jones "It's not unusual"

Way it works is that the oil tank is higher than the sump of the engine so when the engine is not running gravity will fairly quickly allow oil from the tank to run back into the sump.

That reasonably quick process then slows to a crawl as trapped air prevents the oil from rising in the engine any further, but as that trapped air gradually finds it's way up into the tank or rises up in the oilways of the motor then it will allow the sump to fill some more until after a fairly long time. (maybe several days) it will even disappear from the sight glass altogether or be very low.

The moment you start the engine all that oil that ran back into the sump gets purged by the low pressure pump back into the tank hence it rapidly rises again whilst a bit goes via the high pressure side to the motor.

It's all by design to be that way.
If all the oil stayed in the tank and it sat lower and couldn't then feed back into the motor by gravity in the qauntities it does then the motor would be almost completely dry for the first few seconds after startup and excessive wear would occur until the oil got from the tank to the pump in bigger amounts.

In short, don't panic it's meant to do that sir.

The oil should be on or near max when running and what it does at all other times doesn't matter.

Thanks for the advice Spoonz. I was pulling my hair out over this problem. I gather then that it doesn't matter that the oil has stuck on MAX level when cold?The only niggle I still have (please be patient with me on this) is your comment re: "The moment you start the engine all that oil that ran back into the sump gets purged by the low pressure pump back into the tank hence it rapidly rises again." If my oil level is already at MAX when cold, will the tank not simply overflow on start-up and flood my airbox (or wherever it goes)? Its just that my oil level isn't dropping back to MIN again (or at least hasn't moved for a day now).

178Mannyroad said:

Thanks for the advice Spoonz. I was pulling my hair out over this problem. I gather then that it doesn't matter that the oil has stuck on MAX level when cold?The only niggle I still have (please be patient with me on this) is your comment re: "The moment you start the engine all that oil that ran back into the sump gets purged by the low pressure pump back into the tank hence it rapidly rises again." If my oil level is already at MAX when cold, will the tank not simply overflow on start-up and flood my airbox (or wherever it goes)? Its just that my oil level isn't dropping back to MIN again (or at least hasn't moved for a day now).

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Max when cold (like next day or a few hours) would be unusual and i would say overfilled.

Are you checking the running level with the bike upright ?
On the sidestand you will get a false level.

178mannyroad,
i shouldnt worry too much, i was really worried at first about my oil levels too - when cold it appeared to have none in! but when warmed up it reads above the 'min' level, and sometimes above the 'max' level too! (when stood with bike upright and hot-74c) apparently according to jussi the level will also fluctuate slightly due to atmospheric conditions (ie local temperatures when bike is cold).

spoonz said:

Max when cold (like next day or a few hours) would be unusual and i would say overfilled.

Are you checking the running level with the bike upright ?
On the sidestand you will get a false level.

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Spoonz,
I am checking with the bike upright on two wheels and it is still sat there at MAX level. I think I may need to lose a bit of oil. Must say, you can't beat the Japs in this area of bike maintenance for simplicity.

Jwer,
You've got the same machine as me so its reassuring to hear yours is up and down. Not had the bike long so not used to the oil checking procedure yet.