Excuse me, are the piston pins of horizontal motorcycle 50CC, 100CC, 1 10CC the same size? Can they be used universally? Because I want to change 50 into 100.

Piston pins are generally larger and more common, but there are many problems. First, the cylinder block of 100 will not fit into the crankcase. You must turn off the outer ring of the cylinder block with a lathe. Second, the shortened crankshaft needs to be replaced 100 crankshaft. Third, the timing chain needs to be replaced with two short sections. Finally, the valve of the cylinder head is too small. Finally, the cylinder head and valves can be replaced by engines. If you really want to change it, I suggest you change it to 70, because the crankshaft timing chain and cylinder head valve are all right. If you don't understand anything, you can communicate with me. I hope I can help you.