hm... no idea. seems kinda neat... looks like it runs a chain to one of
the smaller sprockets on a mtn bike, requiring either a cheap mtn bike,
10-speed, or something with a spare front chainwheel and diamond frame,
wouldnt work on my aluminum frame monoshock.

The kit comes with its own sprocket. Another site sells nearly
identical kits, and shows adding the sprocket.

OTOH... it also looks like it will require a LOT of tinkering,
adjusting, fitting, etc to get it right. and the engine is a complete
unknown.

It's 'supposed' to install easily on a bike with a 70 def V frame, with
not mods.