One can fabricate one from a long bolt that fits through the pin, a length of pipe just a little bigger than the piston pin.
A large washer on the end of the pipe and screw a nut on to pull the pin into the pipe.
You may have to grind the head of the bolt down to fit through the pin hole in the piston.
Take a look at the one in the link and copy the idea, it will cost less than a dollar to make.