I know that this is a completely farsicle idea but imagine this little beaut on a bike, its relatively light at 15kg (33lbs approx) but is pushing out 50bhp 
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and i know before all the synics out there critisize you would need to build a very strong bike to run such a thing but the parts are out there

kart parts, kart spares, lrg karts, rotax, kart accessories, karting, prokart, racewear, zoom karts, kart racing, kart shop, go kart, karts, tkm kart, racing kart,asm engine,did chain,sprocket,go kart parts,zoomkarts,magnum clutch,arai helmet,parts,c
and i know before all the synics out there critisize you would need to build a very strong bike to run such a thing but the parts are out there