GY6 139QMB 100CC 50MM BBK problem

Discussion in 'Newbie Scooter Tuning' started by Tautvydas, Sep 3, 2019.

  1. Tautvydas

    Tautvydas New Member

    Hello guys, I have a 2007 noname GY6 chinese scooter. I recently fitted my new 100cc big bore kit+big valve head ,but the scooter can't achieve more than 40mph. The same thing was with my old 70cc kit couldn't go over 40mph. I have a 17,5mm carb. The head is ported intake and the washer too. CVT is stock except 8g rollers.
  2. Stevep

    Stevep Well-Known Member

    un-restricted cdi, sport exhaust

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