New one has bigger transfers and a simpler boost port. Transfers are better angled too. The previous arrangement is not something I've seen before. The old piston is Yamaha RD style with the 2 slots - maybe that's how it got that way on the old engine?
Exhaust might be a bit narrower - can't see tho'.
Piston looks a lot sturdier and the pin is height-centred more like other 2-stroke pistons.
The original system looks a bit, um, strange!
Thanks for posting this thread Hughes500E
