Flathead, thank you for you response. I guess I need to ask some more questions.

1. If I get them out like that how do they go back in? I guess I could find a shop that had a press and get them to get it out and maybe put it back but that is kinda iffy.

2. The Ryobi was simple in that when I took the jug off the piston came right out. It has two rings and from reading the threads on RCU I take that to be good. The Poulan on taking the jug off, I could not get the piston to come out. There is something holding it and so far I have not been able to see what that is. I also want to replace the rings.

3. I will be buying the conversion parts from Jags.

The reason for doing this is that I have always wanted to design and build a plane of my own. If all goes well it will be something high wing,symetrical, and maybe about 80 or so inches span. I am just getting back into rc after about a four year hiatus. I left Florida to attend my Fathers funeral in Tenn and had all my rc stuff stolen while I was gone. That took the wind out of my sails until now and the only way I am going to get back in is with a conversion and an airframe of my own design, win, lose or draw.

Again,Thanks much

Bill