What's causing sludge in my exhaust port?

[bootlegger]

Removed my exhaust and discovered this goo in the number 1 exhaust.  I don't know that # 1 was missing or anything.  This was a cobra exhaust, so I did have a lot of popping and burbling, but nothing really unusual.  Any obvious suspects here?  I have not opened the valve cover yet, but I will do that to inspect.

Thanks for looking.

[hubcapsc]

You look desmogged. If you still have the OEM petcock, there's
a vacuum line from it to one of your chrome intake runners.
The vacuum line doesn't usually go to the one I'd call #1,
but I guess someone could put it on any one of them, especially
on a desmogged bike where they're all available.

Anywho... if your gooped-up up cylinder is the one with the
petcock vacuum line, it would be worth making sure your
petcock is OK and not sending drool down the vacuum line.

-Mike

[bootlegger]

No drool.  The vacuum goes to # 6.

The goo does not smell of gasoline, so I don't think it's coming from carb leakage.

Thanks

[da prez]

  Run a compression test on it. You may have a compression ring leaking.

                                 da prez

                           

[Mooskee]

Were you getting smoke out that exhaust pipe?  Perhaps is is just a valve stem seal leak. Run com pressing check to verify it is not piston rings. If not might be valve stem seal . Not too bad to change with head still on.

[h13man]

It appears that you maybe had a exhaust gasket leak as the port next to it appears pretty clean.

[WintrSol]

It appears that you maybe had a exhaust gasket leak as the port next to it appears pretty clean.

From the stain around the stud, this may be it.

[bootlegger]

Thank you for the replies.

After further review, I believe an exhaust leak is the most likely culprit.

What looked like sludge was really just a wet spot on the ledge of the head.  There was less there than what it looked like.

Compression was good.  It does not smoke or burn oil, so if the valve seal is leaking it's not leaking much.

I will put my new to me oem exhaust on, keep an eye on it, and call it good.

Thanks again