The engineering concept is poor. It would need a very short stroke and a very compact head to avoid the crank being set too far back for a decent length swingarm/reasonable wheelbase. The photo clearly shows a short swingarm so it'll struggle to handle well.Kawasaki's 650 parallel twin is an excellent concept because the engine can be very compact, allowing a forward and narrow crank, and thus a long swingarm, all of which combine to give potentially excellent handling. Unfortunately, Kawasaki then gave the ER6 cheap suspension and a non-rising rate linkage...oh well.One of the most interesting concepts is a narrow angle asymmetric v3 engine - imagine a parallel twin with a third & larger piston offset at 35 degrees to the twin and connected in the centre of the crank. Kind of like half a Vorex narrow angle V6 but with different piston sizes to achieve better balancing.Although more complex, it works out to be only slightly larger than a parallel twin but can produce a significantly higher output and still maintains a forward and narrow crank, long swingarm, etc.