I tried to reply on your blog, but don't know or it worked.
Beautiful work and magnificent photography.
By Law in Holland the Sinclair is officially a E-Bike. That means, you can drive it on bicycle roads etc with a max speed of 25 km's/hr. The first 6 km's it may work on the engine only, but after that the engine should be pedaling supporting. So building in a 7 gear shimano is a good option, youre otherwise pedaling your butt off.
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Hope to see your creation on the First International Sinclair C5 meeting in juli this year in Zutphen.
In fact, no policeman that ever stopped me, even knows the sinclair c5.
Its a bike, its electric as well. No problem. They have a smile on their face and ask where you can buy one.