Modern Buddy

Went to a 72cc kit, big increase in low end torque
not too much on top end speed.
I weigh 190 and looking for a bit more top end. Right now about 45 mph on a flat.
What weight roller you think,
9 gram?

Did you pipe it as well? Airbox opened up or swapped? Restrictor taken out of the CVT?

Rollers alone won't increase your top speed much. It's all in the mechanical physics of the engine/gearbox. In order to get more top speed you have to either increase the engines operating RPM or change the gear ratio in the gearbox. This is assuming all of the speed restrictions have been removed from the engine.