Shaka is right on the money! An open filter, w/ re-jet will add 4-5 mph topend, and get you there Quicker. The cdi will benifit from lighter rollers, as you will have more available rpm's from the engine. I have a Malossi 47mm Cast iron jug kit, Cleaned up the casting, milled .5mm off the head, and opened the exhaust port to match the pipe, which is the Technigas r-2. I use Boysen reed material that I cut to fit. from a yz 80 Yamaha (.30 stock carbon fiber). 28mm Delorto phbh carb, K&N type air filt. Malossi multi var, and Malossi Delta clutch w/ yellow contra & fly springs. 5.5gr Malossi rollers, and Malossi Kevlar belt. Before I owned the scoot the orig. owner had Polinni secondaries installed. The final ratio is 8.3:1. Same tires as Shaka. I also re tuned the silencer w/ 4 wraps of fab mat glass cloth. (sometimes I use it and sometimes I leave it open). Also a Racing ciol from Provo Scooter, w/ a factory plug boot. And of course the Suitai tuned cdi. I steadily reach 62-65 w/ a fresh piston/rings. Cruises at 50-55 w/ room to spare. (I can easily pass cars doing 55). I am looking for a stiffener kit for the frame tho. Hit a hole at 60, and you feel the frame flex more than I trust. All this took about 3-4 months of trial, and error to set up. but it is a good recipe for the zx/superfever.
