I finally got around to repairing the friction roller wheel on a Free Spirit motor. I must also admit, I got the idea from a guy at a Bicycle show.
First, I removed the roller from the motor, and wire wheeled all of the plastic crap that breaks off. I found radiator hose that fit on the thing snug and used some 3 minute Loc-tite epoxy from Wal-Mart. After the first one was dry, I installed a larger second piece of radiator hose right over the first. After this dried, I trimmed the ends and reinstalled the thing on the bike. It works very well.
I've also figured out that a good working primer bulb on these is critical to getting all of the fuel circulating through the carb or it WILL NEVER START. So if you remove a carb to clean it, lube the black primer bulb with something so it doesn't crack. When you squeeze it, it sould criculate fuel through the carb.