Namura Piston

Ditto on what Mihylo said. If your son ride half as hard as you say he does you'll be doing more than just replacing a top end in shorter than normal time. But this is just my opinion, based off of alot of other opinions about this topic
well for 45 dollars vs. 75 I went ahead and got it. I figure he'll probably have wore it out or blow it up by the end of summer. Then I will have some more money or he will to get the 85 cylinder replated and he already has the 85 top kit from Wiseco sitting on the closet shelf.