I'm doing battle with my advance housing. And I'm losing.

[Soliddrummer]

Here is the lowdown. I have an oil leakage at the advance housing. I have installed mikes new style seals, new gasket and new o-ring. Polished the end of the cam before install of the new seal. Polished both sealing surfaces, housing and head area for perfect mating of the gasket and o-ring. Im using new screws with lock washers, torqued to factory spec. It is still leaking. Not a lot, but enough that after I ride to work (30 miles) I have oil blown all over the right side carb/intake and side cover.

It appears that the oil is not leaking from inside the housing, which means the seal is sealing, which in my mind means that there is a breach of some kind in the gasket/o-ring fitment. I have had this housing off five times now and everything appears perfect. No old gasket material or gunk causing the gasket to not seal properly. The o-ring groove is spotless.

Can I and should I just put a thin coat of gasket sealer like yamabond of three bond on the gasket and o-ring?

Any other ideas? Is there anything I could be missing?

 

[5twins]

Have you had the topend apart and the cam out? If so then maybe you didn't seat the bearings in all the way on that side that's leaking.

 

[Soliddrummer]

Thanks 5 twins, I did have the engine apart when redoing the top end. Is there a way I can measure to see if the bearings are not seated properly? Or is the only way to know to take the valve cover back off and check?

 

[5twins]

Well, you could check the depth of the bearings on the other side and compare that to what you've got on the leaking side. I know it looks wrong when you're assemblying the topend, but the bearings need to be slid in as far as they'll go on the cam. They end up hanging off the bearing bore in the case on the inside a little, but that's how they have to be. If they aren't, the points and advance housings won't seat in far enough to seal. This could very well be your problem. This is how the bearings should sit. Notice how they hang off the inside of the casting a bit. Looks wrong, but it's not .....

 

[XSLeo]

One thing you can try is to loosen all the head bolts. Lift it a bit.
Enough to relive the pressure on the bearings.
Get a socket or piece of pipe that slides over the end of the cam. It should ride on just the inner bearing race. Now tap the bearing in until you see the cam move out on the other side. This means the bearing is on all the way. Repeat from the other side. This ensures both side are in all the way. Now using the wire depth gauge part of your dial calipers measure both sides. Move as needed to get both sides the same.
Once they match your cam is centered. Now retighten the head bolts.
Leo

 

[Soliddrummer]

Thanks Leo, I'm gonna try that, I did take the housings back off and fount that the advance side is about 1/32 of an inch deeper than the points side, it seems to me that indicates that the cam is not perfectly centered and would certainly explain why I'm not getting a good seal on that side. I'm going to try this method of centering the cam and I will report back.

 

[Soliddrummer]

Ok guys, I did as Leo suggested and centered the cam, it was off by just a hair. NEW gaskets, NEW o rings, and this time I even used a thin coat of 3bond on all surfaces for insurance......still leaks. I am absolutely certain that the leak is coming from this location (behind the advance side housing) and not coming from somewhere else and migrating over. As you can imagine my frustration levels are very high. And now that I've used 3 bond, I'll be needing YET ANOTHER set of gaskets and rings when I take those housings apart.....again......My only thought is that maybe at some point in my bikes history the valve cover had been replaced, so the valve cover and head would NOT be a matching pair and maybe my leak is a result of this mismatched pair of components.

I am just guessing at this point.

Any ideas?

 

[XSLeo]

Look at the head and the rocker box between the exhaust pipes. There is a 4 digit number stamped into both. They should match.
Leo