yeah i was thinking of how i could accomplish swapping the disks to the bike.. looks to be sort of troublesome though but im sure it can be done.. that will be a project i will probably go after once i get the engine setup and tested ect..
i have also found a larger front sprocket for the goped engine it should increase the top speed to 47 mph or so if the 2.5 horse has the guts for that speed anyway.