If the cylinder is a 70cc one it's probably possible. I don't know if the Yasuni R is the right one for this cylinder but you need something to make it rev higher. Maybe a C16.
If you replace the cylinder for a 70cc one and you use an exhaust that won't let the engine rev higher there will be not much increase in topspeed. It will just accelerate faster. Instead of using longer primary gears up the revs for more top speed.