Im looking at buying an '01 YZ125 but it has been bored to a 144 and stroked as well. My local MX Association does not allow an engine to be stroked but it edoes allow it to be bored up to a 144. Is there a way to cancel out the stroking by buying a new part or would i have to buy a whole new thing and get it bored again?
I would say you need to replace the crank and the rod back to stock. usually if you stroke a motor you put a longer rod and a crank with more throw. and new piston and rings.
ask the guy what he did to stroke it would be your best bet. and thats what you need to replace.
Check that it really has been stroked in the first place, you may be able to get a measure through the exh port if not you'll only have to pop the head.