You can't really adjust the transmission on the zinger since it's a centrifugal clutch. You can get different springs, which won't let the clutches engage until higher rpms. Look on ebay for the perfomance clutch springs for a pw50. You may have to adjust your idle down a little bit. Hope this helps.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90