The 400's fascinate me.
At 43bhp it's in the ball park of an awful lot of the popular British twins that once dominated the world. Some of the big ones even aspired to the heady heights of 50bhp...!!
That is just over 100bhp per litre too, so very respectable really.
With appropriate low gearing and, what? a 5 speed box? I would say it's ideal for town riding with the Monster's nimble handling and powerful brakes.
Assuming that you are planning to return to Blighty at some point? I would say that a M400 is one that would be worth bringing home, as we don't have many here...Never seen one myself...Would love to try one out round the local lanes one day...
