Originally Posted by Foot dragger
75 HP,out of a dual purpose single? At the rear wheel? What might be required to have this happen?
Trust me man, you don't want to go there.
75 RWHP is 25% more power than the '12 690cc version makes (67 at the crank, about 60 at the wheel), and more than the 710cc Factory Team Rally bike as well.
You would need the 84.5mm stroke crank (all '12 690 or earlier Duke R), a big bore kit with custom cast reinforced cylinder (108mm bore), head work and high flow valves, bigger cam, bigger injector and custom tune, bigger throttle body, free flowing air box and a dual exhaust system.
This graph shows PS at the crank, yellow is with exhaust noise inserts, black without.
Don't forget that you will need a stronger clutch to actually be able to put the power down. The complete 690 Rally clutch assembly will work, but the cover alone is about €1000, let alone new basket, pressure plate, discs, etc...
A cheaper alternative is the spacer to use the stock LC4 cover and the billet pressure plate made by Engine Art in Germany.