I bought these parts from a guy quite a while back that was going to do the same project I did. Which was put the nsr motor in a trx quad frame. When I did my research on these motors, what I found was they all used the same engine parts except for the cylinders differed a little on different years and the sp models came with dry clutches. Other than that, they all seemed to be the same from year to year. Someone with more knowledge on these motors please feel free to correct me if im wrong because people keep asking me what model these parts came from and I cant tell them because I honestly dont know and dont know how to tell which model they came from.
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Alex