I took the sound from the clip they posted and ran Audacity's spectrum analyzer on it when it was bouncing at the rev limiter. Strongest peak at 569Hz which corresponds to 17000rpm
I would guess 50hp, since 600cc bikes make ~210hp/L with 10% less revs. The ratio was about the same in 1989 between the 250 and 600 bikes.
If this comes to the US, it might get me into motorcycling, even though I'm deathly scared of dying. This bike will only be doing like 45mph at the rev limit in 1st gear which means I can enjoy the sound while lowering my risk of getting killed.