More HP is a bit vague, what for? A few percent is doable but in this game the costs become exponential very quickly. These engines are already very highly developed stock, there are dozens of threads on faffing about with pipes, tuning and whatnot to get very marginal increases, use the search function but good luck working it out as even the experts here are all over the farm arguing over the details. The short version is that to get more power you need more revs for that you'll need a solid budget, and then how often do you want to rebuild it? Finally every bike is a system, a few hp is not going to upset it but any significant power increase will require changes to cycle parts if you want keep it in balance so it still turns and stops. Even if you are drag racing (which is a total waste of this bike IMHO) you will need to lower and extend the wheelbase to realise any advantage of a significant HP increase. Most people find that V4's have a surfeit of power but a deficit of skill managing it
