What are the selection pressures? I mean is it just us seeing if we can fiddle with all the parts enough to make a motorcycle? I'm sure its possible to make a rudimentary engine from metal and rubber (and anything else that bikes are made from. Basically large numbers of designs get drawn onto the bike.
However i suspect you want a little more than this.
1. The only true selection pressures i can think of that could effect bicycles in terms of evolutionary ability would be either speed, power and agility. Unfortunatly im sure there are easier immediate results from simply make the bike lighter, adding suspension, gears etc. There would be way for the bike to develop an engine without losing out to it immediate compadres, and hence the mutation wouldnt be carried on.
2. Assuming the selection pressures are just actually what i want as far as getting an engine to finish with then that makes it easier.
It would take billions of billions of billions of mutations, slowly picking the ones that become more engine like (im assuming i get to have lots of pictures of engines sat next to me so i can tell which of my mutations are getting closer.) Then with enough time, i would imagine we'd be there. Cept maybe for a battery and fuel.
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