It's the SR50 scooter, not the RS50 motorcycle. The RS bikes are cool, the RS125 is even cooler, and the RS250 is just plain AWESOME! The RS50 scooter makes approximately 6-7 hp I believe while the SR50 bike makes 12 hp. Completely different motors though. Both 50's though have fairly large aftermarket followings like Ohlins suspension, big bore kits, and other random bits and pieces that would blow your mind if you REALLY dug deep for the parts like availabe in Europe. There is a big bore kit for the SR50 that bumps it up to 80cc, and 22 rwhp and 22,000 rpm, more than triple from stock. The guys that run these do an extremely low 13 second quarter mile without spray.
The coolest mod I've seen for the RS50 bike though, is the swap over to a KX500 motor
In the past 2 months, I've seen used sr50 scooter just about disappear from the marketplace because they either go extremely quick or no one wants to sell. The ones that I do see go for a rather large sum compared to what mine went for. In 3 months, the scooter's fuel savings is enough to pay itself off and if I resell it, actually make a high percentage profit overall. As for the RS50 bike, a good number of them have shown up back on the market. Not as many has months before, but now they sell for 25%+ more. What I used to see for $1500 is now $2200 for the bikes and the once was $1000 used scooter is now $1400+.
Here in the states though, folks knowledgeable in the SR50 and RS50 are nearly nonexistant along with finding the parts, aftermarket and oem.
I love smoky stinky 2 stroke street machines old and new!

I'm about to make a minor mod to mine that should net me an additional 7 mph to get me into the low 60's. I just need to quit jumping mine off curbs and airing off of the edge of driveways and speed bumps causing me to blowing my fork seals and rear shock! I can barely find fork seals and rear shocks!