1. Are you pulling the clutch lever while trying to start? not kidding, the left lever on your handle bars engages the starter clutch. it looks like a break lever, particularly if you have a model with rear coaster brakes. If that's a dumb question then sorry. It's your first post so I had to ask.
2. What other symptoms are you seeing that make you think rebuild? Are the pedals completely stuck or do they spin without engaging? Are you certain that the starter clutch is engaging? Have you tried taking the cylinder off, does the piston move freely? Is there water damage/rust in the case or are the bearings/seals obviously blown? Did you buy it like this or was it running and then later developed this problem? It could be any number of less serious things and I would try to rule a few of them out before splitting your case.
This will help if you have to rebuild.