With regards to.bike carbs and mpg, i have a mk2 escort with a 1660 xflow, usual goodies, last time.on the.rollers it made 120bhp, in town on ninja carbs it'll do almost 25mpg, on good day, but motorway i.regularly had over 40mpg, my pb was 46 coming back from the pod, but for everyday use I'd listen to the lads above, try n stick with the standard induction etc.