One heck of a day

After a long wait and a couple of case splittings (2 total within a month) I finally had replaced my broken chain guide and what I had thought was the rtv gasket seal for the case halves. On taking it out on the test run I found that I still had a leak and on the way home my muffler fell off thanks to a god forsaken divet I was unable to avoid on the on ramp. (awesome! :?) A state cop came out to help me get it but there was too much traffic, and I will have to wait for another time to retrieve it via state highway officials :evil:. Since the oil leak is from the same place I have determined it is not the silicon seal after all, but a main bearing seal of o-ring, something along those lines. Anyone have a clue?

On a brighter note, I replaced the clutch and throttle cables and it rides like a new bike. No more iffy takes offs due to the clutch and no more non factory cruise control. On top of the fact that I don't think many people have been able to go 0-70 in front of a state cop with the throttle wide open as well as the pipes. :lol:

So my question is, what do you think the oil leak is being cause by? The leak is coming from under the left side Yamaha cover. Where the magneto is and where that shaft enters the case. I need to do my front fork seals as well, if anyone who has done this before could help with the seals and a possible case splitting again, please let me know if you are in my area.

Danvers, MA. About 30 minutes north of Boston

 

I'm not sure which model you have, but is the oil coming from the left side?

The right side, the crank doesn't actually come through the cases (on 85-6 XJ700)
The seal is actually just a plug BUT it does sit is a groove in the cases, so it's possible that it didn't get sealed.

On the left side (behind the pickup coils) there is also an oil seal that may be leaking. The OEM seal had a lip that located it in the cases, BUT the replacement I got did not have the lip. IF you still have the lip, you would need to split the cases to get it out (or possibly butcher it to pieces and pull it out).
The new seal will go it with the cases still bolted together (or at least the one I got will)

You should be able to pull the timing disk off and the pickups and possibly see the source of your oil leak.
Good luck.

 

ummm... since you might be splitting the cases again anyway...

Did you use RTV as your sealer exclusively, even on the crankcase halves around the main bearings?

Because if you did, you're gambling with a big-end failure.

When reassembling the motor, you NEED to use Yamabond #4 or an equivalent semi-drying adhesive gasket sealer. If you can't get Yamabond 4 then a product called ThreeBond 1194 is a direct replacement.

Good ol' RTV simply isn't HD enough. If you used RTV I would strongly recommend pulling it back apart and redoing it.

 

Hm. Alright. I think I will end up doing both. It's gotten to the point where I have almost just gotten rid of the thing. Just been a money hole, although I keep telling myself it will be worth it, it's not easy. I have a 1982 XJ 750 Seca

Well. I wish I had known that the RTV High Temp stuff wouldn't work, in the manual in only says I need a silicon gasket maker, which I picked up locally. Well, I'm gonna give myself a few days then come back and attack it again...at least I know exactly how to tear the thing down and put it back together :lol: :roll:

After this tear down I don't think I'll be willing to do it again any time soon.