It is a fairly easy job to do I had no problem doing it and it was the first time I did it, I had the trike apart so did it with the swingarm off but I see no reason why you couldn't do it on the trike I have seen people do it before, 2 tips for you one put the bearings in the freezer for a cpl hours before you do it and when you take it out it will slide right in easier but make sure you wipe any frost off the outer ring before you install, two make sure you hit the bearing with something the size of the outer ring if you have to hit it and you probebly will a bit ( you can use a socket for this) and make sure it is all the way seated and make sure the carrier tube is snug against both bearings if it isn't you might want to replace as it will cause bearings to fail faster, it is also good to take the seal off is they are sealed bearings and add more grease then put seal back on before install, hope this helped
Trikes
83' atc 110
83' atc 200e
84' atc 200m
84' atc 200x
85' atc 200x
86' P3
Non ATC
2002 blaster sorry lol