Hi,
The test was done with the engine already disassembled from the frame. This means also without carburetors and so on, the intake was completely open to suck air 😉
Since all cylinders were pretty much the same, and the engine was running, I'm not worried.
In the meanwhile, I had already time to check the valve clearance, nearly all of them are too tight.
Anyway, I will go on and disassemble the engine further, the minimum I would like to do is to check the valves and sealings and regrind the seat of the valves.