**** I struck oil while drilling out an exhaust stud

[bwringer]

Couple of points:

1) On a GS850, there is little to no oil pressure to speak of, and certainly not in the top of the engine. The way I usually explain it is that on the roller bearing engines, the oil pump just pushes oil around and up to the cylinder head. The cams then splash oil around. Oil gets pumped up at the back of the engine along the outer studs, and the passages at the front of the engine function as gravity drains that dump into the cam chain tunnel.

2) The oil passage that he drilled into must remain open. It's a large passage, but many of the proposed repairs would or could block it. But I think there's also some room for error here -- as long as the passage is mostly open, a little intrusion by a stud isn't going to hurt anything.


Therefore, I'd have to agree that the OP did exactly the right thing. JB weld epoxy to seal the threads, install a stud, and ride. As long as he took a bit of care to make sure there wasn't a big glob of JB Weld on the end of the stud, it should be all good.

[thausen]

oil passage

Wow....great info ! I was hoping the same thing that the oil pressure at this point would be minimal to nearly nothing. I did not thread the bolt deep into the head but started about 1/8" from the end with the JB weld to seal the threads well. I did not wallow the hole at all and it appears to be well sealed. So far so good. One other thing I found out....I went by and spoke to a master engine mechanic (bikes) who is a friend of mine. I remembered him mentioning that old BMW bikes had studs that actually passed through oil passageways. He suggested to seal with aircraft quality bolt sealant (hi temp silicone type). That's what he has always used successfully on those bikes.

[tkent02]

Some BMW cars have the exhaust studs drilled through, they usually don't leak. Most folks seal the studs in with Locktite.