CB550 Top End Leak? [Pictures]

Hey everyone,

When I bought my 77 CB550 last season, it had the beginnings of a leak on the upper left fins. Wasn't a big deal. Now, it's starting to become an issue, though I still don't have any spray on my pants yet.

Wondering if anyone can throw a few guesses out there as to whether this is a valve cover leak, top end blown etc...?

I have yet to trace to the source (with dye or foot powder) but I know this is not uncommon amongst old CBs.

Any help appreciated. Thanks!

Completely 'normal' on 500 and 550f.
The 'bump' in centre of cylinder is oil feed to camshaft bearings. It's sealed with an 'O' ring dropped into cavity formed by gasket. They get hot and distort causing leak. Usually I wait until it's '3 fins down' from gasket then fix it. (just about where yours is now)
The only permanent fix I've found is to counter-bore oil passage in block and head then fit a dowel to support 'O' ring (plus open hole in gasket)
Running thinner oil helps slightly but isn't a permanent cure

Hey Crazypj. Thanks for the info!

Is this fix something that requires pulling the engine from the frame? Or can it be managed without pulling?

You can remove cylinder and head without pulling motor.
Clamp the two together with the dowels in place and run a longish drill from base of cylinder into head about 1/2" as the holes rarely line up well enough to use as accurate location for case dowel placement
I think it's a 3/16" 'aircraft' drill to bring holes into line (because that was the first extended length drill I ever bought ;D )