When I bought my ultra it had a small leak at the rear right corner of the rear cylinder coming from the rocker box base. I replaced it and the next year it started again. I replaced it again this spring (both times with Cometic gaskets) and replaced the rocker box base because it seemed to be warped a little. Now, after 1300 miles it has started again.


Could the problem be the gaskets? I am thinking of trying again using HD gaskets, but I am starting to think there could be a problem with the head. I didn't see any cracks or low spots when I checked it with a straight edge.


I am getting frustrated chasing this leak! Any Ideas? Should I try again with different gaskets or deal with it til fall and pull the heads (I really don't want to do this, I can see big $$ if I open it up that far)?

 

I had the same problems with two sets of rocker boxes that leaked, and it was all ways the rear ones using cometic gaskets. switched to the HD ones which have the raised sealing surface problems solved. just recently built a 124 & 117 using HD gaskets on the rocker boxes and there is no leaks! also I all ways use blue loctite on bolts.

 

I heard and seen complaints about cometic rocker lower gaskets leaking. Some more than others.. I just rebuilt the top end on a 103 07 egc and both heads were starting to weep on the pushrod side of the passage where the rear head bolt goes.. IMO this is likely the hottest external part of the motor since the exhaust port comes past that bolt. Bike had 65K on the top end tho... If you bike is out of tune, it well get hotter and be harder on the gaskets.

You need to make that both surfaces are flat and don't have any marks in the surface.. I'd use some 320 wet and dry with a surface plate sheet of glass on the rocker cover, especially if it's chrome.

I heard the HD ones are better but I still got a few cometics left over..

 

I second target64 on the cometic rear issue had one many builds ago and never an issue w the HD set. Those plain metal ones simply suck.

 

Thanks for the responses. I will pick some HD gaskets this weekend and give it another try!