Reply To: Very poor top speed GV 125 S
That is correct. It is slower than the older generation GV125 carb model. Thats why we usually resolve this with a 520 kit (less screaming revs, a bit more top end) and uprated clutch pack (so they pack a tiny bit more punch each gear).
15T is too heavy. We dont bother. We drop the rear to as low as 38T on various 125 models. The S EFi gets around 42-48T rear.
See the 520 page for real gps video.
If it has a 520 kit then the issues will either be
- Low compression (runs OK but cylinders need more at high speeds)(wanning)
- Valve Tappets too tight (valves need clearances adjusting)
- Clutch is wanning (knacked springs and plates)
- Plugs? (Look at them and show us and we will verify mixture is good?)
- It hates exhausts without baffles or cans that are stubbies (lack pressure for low down torque)