I have a piston bought for my 1973 CT 175, but now I am in need of a new piston for my 1974 DT 175.
They look and measure the same, except for the windows on the intake side of the piston are smaller.
It sure would be nice if that piston would work in the DT... anyone have Ideas or experience with this set up?

Most matched piston/ring sets can be swapped between the street legal 175 Enduros from 1972 to 1981.  (Important to have rings made for the piston part number used) You can even use a Yamaha Blaster piston if you shorten the skirts slightly to match the original piston.

Also when using a different piston always check to make sure the piston ring locating pins in the ring grooves are positioned so that the ring end gaps pass between the ports to prevent snagging a ring in a port..

Oh, and stay away from the Chinese piston kits.  Some are really bad.  Unfortunately hard to know which ones but they can and do severely damage engines if they fail.