So just thought i'd post this for those interested and hopefully it will help somebody down the road.. If they find it in this 2800 page thread...LOL
I finally got around to converting my worn out 3400 to a 3800. ( and hopefully to a 4000 if a P/C ever comes available for a respectable price).
I made a homemade piston pin puller/pusher and it worked great.
So some backstory... My wife's grandfather brought me this 3400 one day that he found at the dump. It looked fairly clean...had spark but would not start so a $10 carb rebuild and I had it running.. it ran and cut OK but not great..did not pull very hard.. had low compression. only 90psi when hot.. So I found a 3800 parts saw for $35. P/C looked good.
Getting ready for the swap
So the wrist pin puller I made is nothing more than an m5 threaded rod with a nut made solid on one end. an m5 bolt would be ideal, but I could not find one long enough so I made this. on the other end is simply a nut (or 2 to lock it if needed). I ran the rod through a socket with a neoprene washer between the socket and the piston. I put a heavy washer over the socket just to brace it up a lil.
Once you tighten the nut down against the pin, just make sure it is not on the bearings and then you simply turn the solid not on the end and it pulls the pin out into the socket.
Just make sure the nut slides through the bearings
Then just start cranking the solid end and it pulls right through into the socket
Got both of them out in less than 5 minutes a piece
Installation is the same process, just pull the pin right into position
Squish was pretty big on this .05 or so, so I deleted the base gasket. Got it all put back together and up and running tonight. I have not put it in wood yet. might do that tomorrow. Give the motoseal a lil more time to cure and I want to idle it a bit more to let all the new parts get to know each other a little bit more.