Hi, over the past few years my 150 has evolved into a Suzuki 192 conversion, with the help of Reaper Tuning here in Cambridge, using the following:
Suzuki TS185 piston
60mm Mazzuchelli crank
26mm Dellorto PHBH with remote filter
BGM Clubman
BGM electronic ignition
Agusto 6000
Spanish Li150 gearbox -11/14/17/20
46T Crownwheel
15T Front sprocket
80 link chain
Final drive 5.2
It's a great little engine, sits comfortably at 60-65 and has hit 70 using my phone gps speedo app. The same dyno has been used on all the different engine changes, starting at 175cc/11bhp and the best run on the latest build reading just over 15bhp with 11ft/lb torque. I can't tell you the intricacies of tuning the barrel, Viv at Reaper did all the work there, but I love riding this scooter, it goes equally well through town & country, holds its own on the motorway and is reliable for riding all year round to work and just for the hell of it... highly recommended

Good luck, Mark