Hence the fanciful name, G62SLSSEI MK1..The SS is syncro spark..There is a ring pressed onto the front case under the hub..A hall sensor goes in there, you can see the grommet in the rear case where the wire goes through..It didn't get put in yet....Also the carb in the picture is mounted on a scrap rotator block with the holes in the wrong place, and there's no pulse line from the fitting on the front case to the rear cover on the carb...Got in a hurry to put the picture on here.[8D]
The syncro version is lighter because there's no ball bearing on the crank for the mechanical advance, and some lightening holes in the 2 pieces of the hub...Also a lighter mount with slightly thinner walls and square instead of round....It could be a little lighter with a CM6 spark plug and shielded wire, eliminating the outside spark coil and associated lugs on the case...The inside spark coil would be lighter too... 3 lbs 14 oz maybe ?
Maybe some aluminum bolts for the case and cylinder from a 3W....