Forums 🚥 PiT STOP 🔧 Hyosung Technical Help Very poor top speed GV 125 S

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    • #12995
      Billy K
      • Topics: 1
      • Replies: 2
      Kent, England

      So I have a GV 125s, It runs fine and nothing seems to be wrong with it but the top speed is barely 60MPH down hill. It will be on the limiter indicating about 68mph but in reality (GPS checked) it’s about 61 mph.

      This seems really poor compared to what other people report, does anyone know why?

    • #12999
      ♠️ MARCEL
      • Topics: 45
      • Replies: 1,880
      North UK

      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)

      // Meditation doesn't mean you have to sit still....

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