When doing mods on carbureted machines, you need to have a selection of main and pilot jets, at least half a dozen. three bigger and smaller main jets. One size bigger and smaller pilot jets. They're cheap, so don't panic. You're doing rocket science now, and you need to learn to tune your own jets when doing engine mods. NOTE to future scooter hot-rodders: You can't adjust mixture on fuel-injected machines, so you have to leave everything in stock condition. Good luck!