Do you mean the noise/reson for this "sound" ?
Yes, I found it, it was my mistake. There where 2 problems come together, one small and a big one.
At frist I don't have check that the connecting rod bearing was rotating too hard on Cylinder nr. 1 so the connecting rod bearing rotate after a while together with the crankshaft.
And the smaller problem was that I had used too much additional sealing compound between the oil sump and its seal, so the sealing compound goes into the oil sump and if goes there to the oil pump where it closed the filter.
After that I have replaced the crankshaft by one from a CB23 engine from a G100 Charade. This crankshaft was complete the same for the timing of fireing, but the diameter was bigger at the side where the oil pump is. So I increase the diameter of the oil pump cover to the size of what a CB23 engines hole has. (I could not use the cover from the CB23 engine so the engine's block is there different, the CB23 oil pump cover will NOT fit on a CB20 engine (does not cover the complete room from the oil pump), after that I only have to use a new seal ring (typ CB23) and all fit.
Please also note that the flywheel from the CB20 engine will not fit correct on the CB23 engine/crankshaft so it have also a bit less diameter so the flywheel will give you some "tick" noises after mounting, but you did not see it on the first moment, you only reconice a silent periodically "tick-tick-tick" noise. The flywheel from a CB20 (G10 Charade) is full metal, the CB23 flywheel is perforated (4 eliptical holes).
I will attach a few pics from the repair