What are the Dangers of Overfilling Gear Oil?

[Togger]

I changed the gear oil on my B&W 250 for the first time today and I think I made a mess of it. I warmed up the gears by running the scooter a few minutes, but when I drained the oil, only a small amount came out, maybe 50 ml at most, fairly brown. Could it be that the oil was that low all the time, damaging anything, or maybe a just didn't drain it right ? When I added new oil, I think I really overfilled. I added about 180 ml, but if I hadn't drained enough out in the first place, I could have really overfilled it. Can this do any long term harm?

[big blue]

When you say you warmed up the oil did you ride or just run it on the service stand? The gear oil should be drained after a short ride. It is possible that you only had 50ml in the gear case or it did not all come out due to it being too cold and clinging to the cogs. If it was only partially full you probably are ok since there was something on the gears. In order to check yourself you may want to do the change again. This will remove any sludge and you can again check how much comes out. The main problem with overfilling is that the excess might be blown out through the gear case vent tube into the air filter and ruin it. I think the 180ml is correct. Did the oil escape from the filler hole when you added the new oil? If so you are probably overfilled. I suggest draining and refilling with fresh oil.

[de-dee]

   I change then oil hot after a long fast ride,. the first time I did you should have seen the crap that came out, and that was after the dealer changed the oil a few miles befor , 

[Stig / Major Tom]

If this was a used scoot - maybe previous owner did not fill properly.
If in doubt about how much you put in ---- yes, put a little pan under it and  pull the drain plug.....go  away for a spell and let it drain - even cold it will come out if you give it an hour or so at this time of year.

Put in the drain plug and refill with proper amount (per owners manual for "refill" amount, not how much the gear box holds - total. Those are often 2 different measurements. You want the refill amount.) If it is 180ml, that = 6.09 ounces (US)

Take you time - you can do this and it will help you bond with your scoot!

PS: when you get it all buttoned up, give us a picture. We like your kind of scoot here!

[Vivo]

Overfilling may increase operating pressure inside and may blow your seals...

[MaryK]

I think most rear gearboxes are vented to the air intake for the engine.
Probably an EPA requirement ?
Excess oil is carried over to the air intake and can coat the air filter.

Scoot safely,

[boo]

I wonder how over filling could blow the seal if the gear box is vented, Which it is.
How could it build enough pressure to blow a seal?.

[Vivo]

It may not "blow" the seal but still the pressure is there... it may, if the seal weaker than normal, it may not...