1981 XJ650 Oil Sender Leaking

Hello
New to the forum, but have been reading this site for quite some time. Great technical advice on here.

I'm currently working on my 1981 XJ650, essentially cleaning and cosmetics to get it back on the road after a few years of other projects. I have run into a strange situation with the oil sender leaking. I removed it when I cleaned the engine, but previously it was sealing up no problem.

I have replaced the o-ring (twice), installed it with seal-all, even added a small gasket to see if it would help, but no luck. The sender and mounting surfaces all look fine, no gouges from removal. The pan looks fine, as in no cracks. The sender is going in fine, with no pinching on the o-ring. I installed my spare 750 unit and the leak was still present.

I'm at a bit of a dead end. My only thought is that the pan is somehow damaged. Any one encountered this before? It is really holding up the whole project!

B.

 

mine seeps too, the o-ring and pan are good too. here's my theory, the seal where the wire comes out is shot.

 

Well at least I'm not the only one!

The wire was my first thought, so I checked the sender with a piece of paper wrapped and taped around it overnight. Sure enough there was a line at the flange. Also swapped senders from my 750 parts pile. So it has to be the o-ring, I'm in the process of placing an order for new parts with xj4ever and will see what that brings.

For now I have completely drained the oil, cleaned the surfaces (again), and installed the sender with a good o-ring and ultra black sealant. I'll let that sit overnight and then add oil tomorrow. I'm not too hopeful. but right now I'll take good enough so I can get the exhaust back on and the bike up and running!

B.