Springman,
I had the same thought. I changed hundreds of bicycle tires when I was a kid, there was nothing to it. Changing a motorcycle tire is a totally different thing. It's MUCH harder than changing a bicycle tire. Just getting the old tire off can be a real challenge and if you care about your rim crude tools can easily damage it. If you have a beat up rim and you really get off on doing things yourself then have at it, otherwise $40 a wheel for mounting and balancing is well worth it.