Let’s adjust the valve clearance.
Using too much liquid gasket on the head cover will cause problems later. It’s best to avoid it if possible.
Basically, the engine interior is clean and in good condition. Units with poor oil maintenance or frequent overheating end up looking like they’ve been stewed in soy sauce. Once it gets to that point, you need to scrub it or apply wet blasting to get it clean. It’s like a room stained with cigarette tar. It’s not a problem to live with, but the dirt is bothersome, isn’t it? 
#1 EX
#1 IN
#2 EX
#2 IN
#3 EX
#3 IN
#4 EX
#4 IN
There’s slight scuffing on the intake side, but it’s not at a level we need to worry about.
Rocker arm engines have the cam positioned high, so they inevitably operate under harsh conditions. As you continue using them, the cam simply wears down, the rocker arm slippers wear heavily, and the valve noise becomes abnormal.
They don’t suddenly crack or seize, so I don’t think you need to be overly concerned about it.
The carburettor synchronization was barely off at all.
You had planned on carburettor maintenance, but it turned out great that you switched to oil-cooled maintenance instead.
