Originally Posted by Mr.B.
Not my cup of tea, but regardless a considerable amount of skill & craftsmanship are involved.-Kirk
I agree. Reminds me of a machinist who paired a couple of Yamaha late '60s era YDS3 250cc parallel twin engines to form a 500cc in-line four (that shared the same "built up" crankshaft (IIRC, this running and ridable bike appeared in a motorcycle magazine). Some of the machinists in here might consider similarly configured project using a couple of Chinese 2-stroke bicycling engines.
Meanwhile, I'd like to know how many hours these guys put into such machines. Talk about having a love for your trade...
But then again, the $18K asking price for the twin cylinder bicycle engine probably best answers this question.