Trade Yamaha Blaster for Honda 250EX

I have a Yamaha Blaster i have been trying to trade for another 4-wheeler, preferrably a Honda.I have a guy who has a 2001 Honda 250EX that he wants to trade me.I don't know a whole lot about fixing 4-wheelers and he say's he will trade me,but i have to fix the rear hub on the 250ex because the weld broke.Is this bad??Is it a easy fix?Was it suppose to be welded in the first place? Please Help!!!