Picture the scene. I’m conducting a dyno run on a customer’s scooter; it’s a TS1-225 with a big Mikuni 35mm TMX carb and an expansion chamber exhaust. He’s brought it to me because “it’ll only just do 70mph, and all the lads in the club can do 80+mph”. I run the scooter up, and the dyno shows that it has perfect power delivery for the given components and a near-perfect air/fuel curve… I immediately deduce that the dyno isn’t going to improve his top speed situation. So what is? This is
