I know the manual says do not overfill the oil tank, which I believe is an accurate practice for all internal combustion engines, but I've noticed when I change my oil and add slightly less than the recommended 3.5 quarts of oil, run the bike, and then check the dipstick, it always seems to register about 3/8" to 1/2" above the "full line?" I suspect there's always some residual oil left that doesn't drain out (I do change the oil after running the bike and warming the engine).

Is this an acceptable amount of over-fill? The manual says excess oil can carryover to the air cleaner and lead to equipment damage. Some people say it'll eventually burn off, but what is the best practice here?

 

We need some info: what bike, year, etc. But I can tell you if you are on a softail and you over fill the oil tank you can push out the dipstick........ I listened to my manual and put in 3 quarts, as it turns out it should be 2.5 qts.

 

You can always use a turkey baster to remove the excess oil and bring it down to the full mark.

 

I saw a video of a guy sucking the oil out into his mouth, when he over filled it. But I'm no pro so I can't say if that little bit is too much over the safe amount. You could always get a turkey baster (spl) and siphon some of it out. Just be careful and don't let anything fall off into the tank.

 

Ditto. If you overfill the tank it will overflow through a tube in the air cleaner onto your bike and the ground. It isn't good for the air cleaner either.

 

My bike is a '09 Softail CrossBones. I actually put in slightly less than 3 quarts. Manual says no more than 3.5 quarts. Is there any safe overfill mark or should it always be right on the "full mark?" What about people who say it'll eventually burn off?

 

I always go almost 1/3 - 1/2 qt less. Keeps the blow-by oil mess to a minimum.
Also read up on proper way to check your oil, some do it on the jiffy, others do it properly upright.

 

According to my owners manual I'm supposed to check my engine oil with the bike on the side stand. If the engine is cold, it should show about half way on the dipstick and if the engine is fully warmed up its supposed to show on the full mark. But it doesn't matter if my engine is stone cold or fully warmed up, it always shows on the full mark.

 

if you over fill a little bit it wont hurt a thing.. if you have too much oil(to the point it runs back in the tank breather), it will just blow out of the breathers into the air cleaner.. nothing would be damaged. 1/2" is nothing..

 

In addition to your manual saying that the capacity is 3.5 quarts it also says DO NOT OVERFILL, so there really is no amount that it can be overfilled that is a "best practice".

You are correct, when you drain your oil, you are not getting all of it. That is why the following is in your manual, and is the "best practice".

Running the oil level so that it is halfway between the lower hash mark and the upper hash mark on the dip stick is NOT running the engine low on oil.

IT IS NOT LOW ON OIL UNLESS IT IS AT OR BELOW THE LOWER HASH MARK, at which point oil should be added to bring the oil level to halfway between the two hash marks.

The following is straight from the HD manual, and it is the same for the Twin Cams and the Sportster Evo motors-

"The correct oil level should register midway between the FULL and ADD marks on the dipstick.

If oil level is at or below the ADD mark, add only enough oil to bring the level to the middle of the two marks on the dipstick."