u/Immediate_Plant2843

So I have a 2021 genuine roughhouse 50 with a 70cc big bore kit added I bought it used. The issue I’m running into is at higher rpm’s/top speed it starts to basically “scream” and dies I would say above 40/45mph which is were the stock speed ends. I’m new to scooters and 2 strokes and don’t have too much info for the previous seller I bought it from but he didn’t do anything but the big bore from my research it seems I need to get 21 mm carb with a 103 Main jet and a 42 idle jet , I’m not concerned about top speeds or anything super sporty related just want to do the upgrades to help it run correctly and need some direction