How I repaired my cracked frame...

The real sit reaches just the expected position. Cool ! Interesting observation, I noticed after inserting the inner tube, that the crack narrowed to become almost invisible (it was about half a millimeter before...)

Thanks to Andy and his neighbour for this suggestion, a bit more sophisticated than mine, but here is the idea ! Thanks also to Corax for the tip and his experience with similar crack in the wild East ... And thanks to everyone who gave valuable advices on the forum :)