I purchased this part recently and found that the piston will not fit my 1974 MX125A. At first glance, it appears to be a decent fit, however once it was installed and I started the bike, there was extreme compression loss, power loss and piston slapping. I had to re install the old piston to make the bike run well once again.
I needed this piston for a new cylinder jug for my 1973 Yamaha AT3 125 Enduro and when I got it, it came in a little cloth bag with the wrist pin, wrist pin clips, and piston rings. I highly recommend Weisco products.