There is loads of tuning stuf for the two-valver bikes,.....big bore kits (944cc),big valves,fancy exhausts,flat side carbs..how far do you want to go... The SS motor is nigh on identical to the Monster.
Have you tried playing with the gearing? How often do you max it out in top? If not that often, lower the gearing for more midrange punch Engine wise, easiest, and probably best bang per £ is a set of hi-comp pistons. After that, the 944 kit Keefy mentions works well. Allow for some carb setting work. Dyno would be the best route. As with everything, your budget will dictate what you get. You can go to 100bhp if your wallet will stand it
Phil Thanks for the information. My engine number is ZDM 904A2C*079747 so it looks like it is a small valver, unless it comes after that run. The MotoOne performance Notebook is a great resource thanks. As is the information about Louigi Moto.
Oh well to look on the bright side that stops me wasting money on 41mm Keihins! happy, happy, happy lalalalala Looks like the only cost effective tune in the short term is a smaller sprocket and cornering faster!