I purchased a NOS piston at .50 over. Original packaging, properly labeled, etc. purchase a new wrist pin and it is too long. Went to old piston, pin fits. Seems the new pistons pin clip depth is deeper than old Yamaha piston. So, piston could have shipped in original packaging but incorrect or a EC occurred at some point and I’m lost in the numbers. Can anyone offer any opinions on one, the possibility of a shorter pin or why this new piston measures out fine but clip positions are closer together? Possible casting info to identify, etc? Both pistons are marked and genuine Yamaha.

Thanks all for any help you can offer.

I remember hearing about some confusion in the parts list for the 400 pin...

What part number pin did you get?

Here's the post with your answer from Enduronut... a real expert on these old bikes.

yamaha-enduros.com/index.php/forums/1972...ton-wrist-pins#64116

Yep, figures. Assumptions are usually a good place to start. Oh well, another lesson learned. Thanks very much for taking the time for me.