Honda Motor Build ?

I'm not finished with my current project, but I'm already looking foreward to the next one... I'm thinkin' about using a fourstroke motor from a honda dirtbike... like from an xr 80 or xr 100. Has anyone around here used one of these for a build yet? I'm just thinking about how nice those things would work with the kickstart and a 5 speed transmissions already there! I've seen some used complete and running bikes on my local craigslist for cheap. Any thoughts?

None of them would qualify for a motorized bicycle...by the law. But they would make for a nice and fast one!

Here are a few.
http://motorbicycling.com/showthread.php?t=13539
http://motorbicycling.com/showthread.php?t=19007
http://motorbicycling.com/showthread.php?t=22533
http://motorbicycling.com/showthread.php?t=19630
http://motorbicycling.com/showthread.php?t=17198

I am sure that there are more, but that's a good starter.

I'd echo GearNuts opinion about "none of them would qualify for a motorized bicycle...by the law."

I think that kind of motor would catch the eye of law enforcement more then any other. More then a 79c/99cc predator type IMO. To me reliability and power are the main attraction.