Join Date: Feb 2016
Location: Budapest, Hungary
I believe I'm one of the members who have put the most effort into increasing performance of these bikes.
120 hp from a long stroke normally aspirated engine is not feasible and borderline possible only. Heck, getting real 120 rearwheel power from a 600RR is difficult, and that bike is built for power and revs to the moon.
Realistically the cost benefit ratio starts to diminish around 60 hp on this engine, but even then a used cbr600f, a street triple r, or a even a cbr650f will be way faster bike than this.
A complete rework with stronger conrods, custom lower comp pistons and a large (relative to the engine capacity) turbo could potentially deliver 120hp for a short period on the 500, but the bottom end or gearbox of this bike has not been designed to withstand that amount of power. I've seen a custom turbo build in Thailand ehat was pushing 70hp, but was already not really reliable.
We haven't got to know how much you've rode since the moped experience with Pap, but my assumption is not that much.
From a budget of around 2500 i'd spend 250 on good quality road tires which fare well in damp conditions if you're sill around lake erie (e.g. a road 5 Michelin or similar) put another amount into upgrading the suspension, spend the most on rider training and track days to learn how to ride safely and fast - and keep the rest to put into another, more powerful bike.
The CBR500 is a great learning machine what has a rounded package of usable power and moderately good handling. I can hang around guys with moderate riding knowledge on big bikes both on and off road with my moderately powered 500x, but I know where are the limits of these bikes. The 500r is a sweet package but it's not unique or the holy grail in anything. If you want that much more power, you gotta look elsewhere.