Hello everyone, so long story short my YBR's top end is just a bit lacking. It will happily sit at 50mph and will push to 60mph. I would prefer if it could happily sit at 60mph and push to 70mph. The only real mod I could find for this bike without spending serious money was an eBay 150cc kit for around 80euro. I think it will probably be a bad idea to buy it but kind of hoping I'm wrong, so if anyone more knowledgeable than me could shed some light that would be great I also don't want to change the front sprocket for more top end at the cost of acceleration.