600cc Engine size, price and location. fabricating it for a fl-250 honda Odyssey?

Its a 1980 something honda odyssey fl-250. I am having issues with the stock 250 motor's stator assembly. I am also tired of putting money into this engine. I had the idea that if I do a little fab work, and a lot of scratching my head I might be able to find a crotch rocket that someone wrecked, that I could pick up for cheap, and take the engine/tranny from it to fab to the odyssey. I realize this will be a lot of work, but not impossible. My plans are to get a 600/1000cc engine and tranny from a cbr or similar. Mount it on the rear of the cart. Remove stock gear case/centrifugal clutch. Then fab the mounts, and use the same chain drive to a sprocket on the rear axle (live axle). The shifter will hopefully mount up to my left side (while driving) and place a mechanically actuated clutch pedal in the foot well. This would use the same stock shifter, new clutch assembly, and still be able to give it some gas while shifting. {gas on handle bar on right side, brake same on left} The issue thus far has been finding an engine that someone crashed, but that is still in good shape with the tranny, for a somewhat cheap price. Once I have that, then the fun of getting it all to go together starts. I for see a lot of welding, moving the seat, and lots of $$ going into this, might be cheaper to build one from scratch... but where is the fun in that.

Any help on finding an site to look at engines (other than auction) and any input on how ******* dumb i must be is welcome. Also if you have anything that might help, be it a engine/tranny, or even some way to hook it up in mind let me know.

btw i live in the akron ohio area... so if you know of a salvage/junk yard with sport bike engines/trannies thanks so much.