Over filled oil...

[Berty5000]

Hi chaps.

I got a service done the other day - reputable garage, very experienced mechanic and motorcyclist - I'd told them that the bike loses oil over time so they kindly put an extra 200ml in to keep me going. Over the maximum line. So the sight glass is  full. They explained this to me and I queried whether this is bad for the engine, putting seals under pressure and so on. I'm a bit OCD about doing things by the book, but didn't want to get into a disagreement with somebody who knows their stuff. They said that 200ml over won't do any harm - would take quite a bit more to cause damage and said they overfill their racing bike by up to 500ml to reduce the need for pit stops (they are an accomplished racer).

But... it bothers me that it's been over filled and I'm convinced that the bike feels a little more sluggish. Bearing in mind it has new plugs etc following full service I'd have expected better performance.

Thoughts?

[The Doctor 46]

Berty, I think you are probably imagining the sluggishness and also, if they are an established racing team and have overfilled their race bikes in the same way then I would be inclined to believe them.

I would guess that the view of our helpful members will disagree but probably haven't tried slightly overfilling in a performance bike but just going by what is written in books. I'm no mechanic but when a good mechanic gives me advice, I take it. 

[mr_diver]

Comparing a race bike to a road bike is like comparing an F1 engine to a Zetec in a Fiesta

The Zetec is designed to last 100k+ miles, the F1 engine is designed for a given amount of laps then explode - so I wouldn't be doing to a road bike engine what is fine in a race engine.

A little over filled ~200ml in my opinion will not cause too much of an issue.
Afterall it's very difficult to hold a bike perfectly vertical to get an accurate gauge of the oil level.
There is one owner, who filled his bike to the bottom of the filler hole and went for a ride.

The excess oil was pumped up the crank case breathers into the airbox and was going down the intakes and getting burnt, but very nearly causing a hydrolock.
He was lucky, but 200ml is nowhere near the amount of oil he put in.

IIRC I used to slightly overfill the oil by 150ml on my DL650 K6 as I found it would use a fair bit of oil sitting at 5k on the motorway commute I had.
200ml at the bottom end, particularly with the engine running is not actually going to raise the oil level very much.

[Berty5000]

I suspect you're right, Doctor. On the way home I started to think the bike felt pretty good. So probably was my imagination

Most likely is that having the oil changed and having 700ml more oil than before (it had been at the low mark but is now above the high one), plus new spark plugs, will have meant it did feel different in some way. Not necessarily bad, just different to what I'd got used to.

Thanks also, Diver.

I've just done the oil level check (3 mins on, 3 off) and the oil is very close to the top of the glass. There is a small air bubble at the top. I find it hard to believe this additional amount of oil, not too far above the high level mark, is going to do much harm. As pointed out by Diver, with the stupid positioning of the oil level, tipping the bike slightly one way or the other whilst I'm reaching down with a small mirror can also make the difference in how the oil level appears. On the centre stand there's a very small bubble at the top - so the level is at the top of the glass, not above it. It is useful to hear the example of the chap who massively over filled - I'm guessing he added more like a litre too much? And still didn't cause permanent damage.

There is the option to put the pipe of a spray handle, from a spray bottle, through the oil hole and squirt some excess oil out (this is an online hack for those who've over filled and saves having to empty it at the sump plug), but I won't bother. Knowing my bike and the way I ride it, the level will be down before too long.

[kwackboy]

200ml is nothing.... your engine will be fine ..

I've had customers who top their oil up on the side stand thinking its under filled and ridden over 4000 miles with no issues.

It'll take a lot more than  200ml of oil to damage your engine .. 

[Barbel Mick]

As above. 200ml will be OK.
In fact, you stated that there was a small air bubble at the top of the glass when the bike is on the centre stand? That is usually a good indicator that when the bike is on the wheels & vertical, the oil level will be about right. 
I've overfilled mine a couple of times & although never rode it like that, I used a large syringe & some of that clear pipe used for air feeds in aquariums. Shove the pipe down the filler hole & suck the excess out.   
   

[Berty5000]

Thanks lads. That's put my OCD at rest.

It seems to be one of those things, like health issues, where using Google returns a load of doom laden responses.

One of the main things people were talking about isn't to do with blowing seals or such but that the oil would come into contact with something or other, get frothed up, and then not be taken up well by the pump - so that too much oil can result in too little where it is needed.

[Barbel Mick]

I think they're talking about a 'proper' overfill where the crank is sitting in the oil & when it spins it's churning the oil to a froth. I think you've got to put more than 200mm in to get that. 

[pb]

Hi Berty. I have had my 2016 650 from new and I found that it used a bit of oil in between services until it was properly run in , maybe about 5,000 miles. Since then it has never used a drop so don't know how new your bike is but may be worth thinking about.

[Berty5000]

Hi pb,

Mine is a 2018 with 16K on the clock and it will lose half a litre over 2000 miles of riding. It seems to be common with lots of riding over 70mph. There are threads about it on stromtroopers. One chap over in the States reckons it is to do with speed specifically, not revs, and something to do with what happens to the air flow, combined with the shape of the filter (?), so that oil-laden air gets blown around where it should be taken back into the bike and goes out of the bike instead (excuse my non tech terminology). Regular riding at 85 or more will see oil disappear. I now have a bottle of oil for future topping up.

People need to be aware of this with these engines because you can easily run out of oil whilst touring and this nearly happened to me a couple of years ago on a 3000 mile trip. Others have reported similar.