Oil Leak (Again)

[XJOK2PLAY]

What I observed was on the XJ head to base, it notches out in the rear middle.
I believe the head bolts don't apply enough pressure to the gasket in that region, and unless you use the higher quality gasket...(which is thicker) it won't seal for very long.

It was sort of a Yamaha design flaw, IMHO.

Just don't waste your time tearing it down and using one of those green gaskets that come in a kit!
If you do decide to tear it down and replace it, buy the seperate base gasket from Yamaha... It's far better.

BUT, I still won't guarantee it'll hold as long as my quick repair method.
As I said before, I feel it's due to not enough head bolt pressure there.
Good luck, whichever way you go.
Bob

[XJOK2PLAY]

Ian,
I just saw your sig says you got a '79 F?
I thought you had an XJ.

Can you tell me what that area is made like on yours?
Does it go straight across the back, or notch outward?

All the XS's I've seen go straight across....no outward notch.


Anyway, regardless... TC was steering you the right direction.

[BA80]

Thanks Bob. Nice talking to you.

[IanDMacDonald]

Bob, right? Thanks for the info. It sounds exactly like your leak. I used the gasket from the gasket kit.

[XJOK2PLAY]

You bet, Ian.
Hope that helps ya get it fixed.
Bob

[IanDMacDonald]

[BA80]

That link doesn't work for me.

[IanDMacDonald]

I just went out there again and really looked at it. The leak is not where the head meets the cylinder, it's where the cylinder meets the engine block. Right in-front of the oil pressure sensor seen in the photo. It's not a straight edge, but rounded in the shape of cylinders.

[BA80]

Yes Ian, the base gasket. That's what we've been talking about..

[XJOK2PLAY]

Yes, that's the same area mine leaked at.
Interesting...

[IanDMacDonald]

https://www.dropbox.com/s/ldkbpov9vlaalcd/IMAG0401.jpg

[Ken Talbot]

It really seems unlikely that you'd have a leak at the base gasket when you just replaced the head gasket with a new one. More likely there is something wrong with the cam cover gasket or one of the half moon rubber plugs not sealing properly.

This old thread talks about the baby powder method of tracking down and confirming the origin of an oil leak.

Might be worth a try...

[IanDMacDonald]

Hey Ken- I've read a lot of your posts in the past. Very imformative. Educate me on what the significance of the half moon plugs are with regard to the leak. I'm curious, as I performed the head job last year with no leaks seen after running it all season. No head bolts were touched during engine out and paint over Winter. However, I replaced the half moon plugs with new from Mike's during the re-paint. I'm 99% positive the leak is from the base gasket, as it is dark at the gasket, and dry above it.

[Ken Talbot]

The tricky part with oil leaks on the XS11 motor is the way the oil can seep out of one place, ooze down, then get blown back in the airstream through a number of front-to-back air cooling passages between the jugs. It gets to the back of the motor a couple of fins above the base gasket, then seeps down over the back of the motor, and accumulates where the jugs meet the crankcase.

Chances are, there is also a build up of sand and grit on the top of the crankcase in this area. Dabbing a Q-tip into those air passages is another way to find oil that is making its way from somewhere on the front side to the rear.

[Radioguylogs]

It really seems unlikely that you'd have a leak at the base gasket when you just replaced the head gasket with a new one.

I once caused a base gasket leak on an XS-Triple by pulling the head. I didn't realize it at the time, but the cylinders lifted a little when I broke the head loose. The base gasket hiked up into the wrong place and seated incorrectly. Unfortunately, I had to pull the head a second time to fix it.