Thanks for the reply Reino.
When you say "brown line" do you mean the gunk/oil? The gunk I found did extend to the outer edge above the exhaust port. Only found it after taking the head off.
The piston has a nice amount of black carbon on top.
I have been riding with the tank cap loose and with a fuel filter in the line. Any links to a relatively straight forward carb clean instructions would be much appreciated. The carb was cleaned and adjusted not too long before the top end rebuild.
How about heating the gasket on a stovetop, DIY style? Is that a no no? I have ordered a new gasket online because I've read mixed opinions on reusing copper head gaskets. I originally installed the new head gasket in the rebuild without any heating and no adhesive of any kind. I'm also going to try and check the top of the barrel, under the head for warpage.
Sucking air could be from anywhere, right, including the bottom end?
Thanks for helping out a noob
Originally Posted by Reino
If it was a leaky head gasket you will see that brown line on top of the gasket surface extend from the barrel to the outer edge, you will also most likely hear it leaking.
Did the piston have a lot of black carbon deposits on its surface? If not i would look at the carb, take it apart and clean it.
I do not believe it is your carbs, because you said the engine did not heat up more than normal. But just clean them, you have been riding without an tank cap.
Then when you put your engine back together take the copper head gasket to someone to heat up uniformly with a torch to soften up the copper (let is cool slowly in air).
Also make sure the engine is not sucking air.