The 250R if I remember from younger days it's about 40hp and about 70mph- that's pretty stout/fast!!!The factors I would keep in mind for a manual clutch, non-reverse engine would be that it needs to be as light as possible. Also with a kick starter-provisions will need to be made for clear access to it.
Please keep all of us up to date on what you decide to do, no doubt with that power plant it'll be lethal!!
