I bought a 85 Evo with a S&S top end. I had a wrist pin fail in the rear cylinder. I replaced the jug, piston and wrist pin. It failed again. I've heard rumors about teflon buttons to place over the keepers. I also heard that rod end play might play a roll in this. I looking for alil' help so I can go eat some bugs.

 

You might want to post this in the tech section/motors & welcome to the forum!

 

If the lower end is worn out the rod will not run true on the crank pin and this will pop out the keeper on the wrist pin. Check the rod to crank pin wear.
Teflon pin keepers have been known to wear a grove in the cylinder from carbon and metal from the oil impregnating the soft Teflon and acting like sand paper.

 

Did you check the rod alignment, especially at the wrist pin bushing? Twice in a row is telling you it may not be square to the cylinder bore.
Ron

 

If a wrist pin walks past the clip,(under the assumption that the clip was installed correctly)chances are the crank needs to be looked at, as the rod(s) is side-loading the pin.