This aluminum cylinder head is new, it is sold naked. Before mounting on the cylinder a break-in of the valve is imperative. To do this, simply do it either with a special break-in tab or with toothpaste because they contain small particles for breaking-in.
This break-in is necessary because the valve seat is rough cast and must be made with the valve that will be in place.
This cylinder head is mounted on VéloSolex 2200 3300 3800 5000