The Tillotson butterfly carburetor with integral fuel pump & hi/low/idle external adjustment knobs is probably the biggest news besides the obvious displacement increase. Note the pulse line “adapter plate” in front of the reed valve intake manifold.
Not exactly sure why they aren’t sticking with a 125 cc format. Guessing the engine will spin relatively slower & therefore wear less…? I’m also curious to know what the bottom end bearing spec & dimensions are.