3AJ Leaking Oil Reservoir
 

I recently serviced my '89 3AJ. As part of the oil change, I removed the oil pipe from where it attaches to the bottom part of the oil reservoir, cleaned it up, put new O-rings in for the two fastening bolts, and re-assembled. Since doing this, I have had a small oil leak from the fastening bolts that drips onto the exhaust pipe and makes a lovely burned oil smell when I ride. When the bike is not running and the oil cools down, the problem disappears, as the cold thick oil does not leak.

I am not sure what is causing this. I suspect it might be a missing O-ring - between the 2 fastening bolts, the metal mesh oil filter is inserted, and possibly this needs an O-ring. I am not sure what size this O-ring, or the other two, should be - none of my manuals clearly indicate this.

I have read on the HUBB that small cracks might cause leakage, but this is not the case here, the leak is definitely from the bolts. I have tightened them as much as I am comfortable doing, don't want to risk cracking the thread.

Any ideas?

3 O-rings
 

Cabron, this connection is made with three O rings, 2 around the bolts, and 1 around the oil passage. You´ll see the groove where it is supposed to be when you take the connection off. In addition, the 2 bolts have copper washers.

Hope this helps.

O-ring sizes?
 

Thanks Auke. That does help a bit, I was not sure if the central metal mesh oil filter needed an O-ring. I do have the copper washers in place.

Do you know the sizes of the O-rings in question? It looks like the central one is a bit bigger than the outer two. Would really help to know exactly the sizes - neither my Clymer manual and Yamaha tech spec bother to state the sizes of O-rings used.