Slight Engine Oil Leak

Can the copper washers used on the oil drain plugs be the culprit for a very slight oil leak? I have a very, very slow oil leak, orientated to the bottom area of the engine. I have replaced all the o-rings on the oil filter, and all the oil related (filter and drain) bolts are tightened to spec. I always run the correct amount of oil.

There isn’t enough oil leaking to even fall on the ground, with the bike standing upright. But if it’s on the stand, there is a light coat oil left after a day or so. It is a very, very light coat around the bottom of the engine, but am at a lost as to where it’s originating, since it is such a small amount, and it is not blatantly obvious of the source.

The bike is a 06 450F, with very low hours. It has not always done this, only within the last week or so. I change the oil after every ride, and the oil filter every other oil change. But, I have never replaced the copper washers.

It is not coming out of the black, rubber breather tube. I elminated that possibility by orientating the tube up two days ago with the bike on the stand, but I still have the same issue.

I am not overly concerned at this point, simply annoyed that a bike I take meticulous care of is obviously not as sealed as it once has. :devil:


Yes, the drain plug washers could be the cause. Sometimes people will inadvertantly run the plug down on a piece of dirt or something and cause this, too, but the washers should be replaced every 2-4 oil changes.

To locate an oil leak, first thoughly clean the suspect area. Then sprinkle some talcum or baby powder over it. For places where it's hard to get to, pour some in the palm of your hand and blow it on with a flex straw.

Any oil that leaks after that will leave a very visible trail in the powder leading back to its source.

Great method gray! Not sure if the 06 has an external oil recovery line like the 05 does? If so, did he remove that line/screen and tweak it like I did last month which resulted in an oil leak like stated above?

Since the "tank" is built into the crankcase castings, there are no external lines on the '06/7.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now