Groove in new Cylinder
I have just opened up a brand new 50 cc cylinder and noticed that there is a groove running up from the exhaust port. It is approximately 1mm deep by 3mm wide and runs about 10mm up the cylinder. I have never seen this on a two stroke cylinder before, is it supposed to be there or is it a bodgy cylinder?. I would have thought that a grove like this would allow the hot combustion gases to jet down past the rings and cause a lot of damage. The groove looks to be designed into it.