I'm sure a 125 can do 150mph given huge gearing and a good run up with a car blocking the airflow!

I'd imagine an NSR geared for 150mph would completely miss the point of a small two stroke engine...
_________________
MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball