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    • #4634
      Swin
      Member
      • Topics: 2
      • Replies: 3
      Joined:
      Jun 29, 2020
      @swinny
      Middlesbrough, uk
      Gv125
      Points: 31

      Evening all

      New member with carb issues on my little gv125 hardtail bobber.

      Open exhaust and mesh filters as airbox is not an option. Carb is untouched from previous owner with 17.5 pilots and 95 mains front and rear, needle set to bottom groove.

      Was having a nightmare starting and hot running cutting out on me. So i used my gunson colortune to try sorting out the idle and it was rich. Only way i could get the mixture right was to shut the screws completely and turn back 1/4 turn maybe less.

      Im not after power i just want it to run right so i can enjoy my hard work

      Swin

      Gv125 hardtail bobber

    • #4640
      ♠️ MARCEL
      Administrator
      • Topics: 38
      • Replies: 381
      Joined:
      Jun 29, 2020
      @mf448kxn6
      North UK
      GTR
      Points: 4,334

      Switch to size 15 pilots.

      Play with the mixture until the plugs are brown all over if you understand what to do or read from the exhaust pipes as  well as heat coming out of the pipes to . You sound like you know the gist of this.

      Also the stock setting for main jets is 87.5 x 2 usually for aquilas  or rarely 90 front 87.5 rear (silly setup but thats OEM sometimes)

      Best way is 90 front and 92.5 rear.

      The bike will start on the button without twisting throttle or turning choke on in this summer heat. Shooting to 1500 rpm cold then 1800 hot 10mins later (1800 hot is ideal).  The mixture and pilot size is good as well good electrics (coils, caps , plugs crucial but common things to wane starting) as well as good clearances really matter for easy starts.

      This is assumed intake system is complete (airbox sitting on the carb) (secondary airbox on the right of the frame) these 2 boxes matter or the CV carb will always run strange it was made sure intake system stays OEM.

      Assumed also orings under the manifolds arent 10yrs old , cracking etc allowing air under the manifolds but also leaking vacuum pressure to run the carbs right

      Hope this info helps

       

      Let us know how you get on

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

    • #4643
      Swin
      Member
      • Topics: 2
      • Replies: 3
      Joined:
      Jun 29, 2020
      @swinny
      Middlesbrough, uk
      Gv125
      Points: 31

      Switch to size 15 pilots. Play with the mixture until the plugs are brown all over if you understand what to do or read from the exhaust pipes as well as heat coming out of the pipes to . You sound like you know the gist of this. Also the stock setting for main jets is 87.5 x 2 usually for aquilas or rarely 90 front 87.5 rear (silly setup but thats OEM sometimes) Best way is 90 front and 92.5 rear. The bike will start on the button without twisting throttle or turning choke on in this summer heat. Shooting to 1500 rpm cold then 1800 hot 10mins later (1800 hot is ideal). The mixture and pilot size is good as well good electrics (coils, caps , plugs crucial but common things to wane starting) as well as good clearances really matter for easy starts. This is assumed intake system is complete (airbox sitting on the carb) (secondary airbox on the right of the frame) these 2 boxes matter or the CV carb will always run strange it was made sure intake system stays OEM. Assumed also orings under the manifolds arent 10yrs old , cracking etc allowing air under the manifolds but also leaking vacuum pressure to run the carbs right Hope this info helps Let us know how you get on

      I cannot use the airbox due to aftermarket tank and have custom drag pipes with baffled ends. See my profile pic.

      I dont understand why some people have upped to 17 pilot as it runs mega rich. 15 pilots are due to arrive today.

      So 95 and 95 mains is a no go on these??

      Read so many people using 92,95,97 and even 100..mad

      Are you saying 15 pilots (obvious) and 90 and 92 mains will be ok for my setup?

      What about needle positioning? Its currently set to bottom groove.

      It goes like the clappers 2k to about 8k then bogs in hight gears to the point you have to knock down 1 or 2 gears to get it going again.

      Intake has no leaks and has new o rings and sealed with universal blue for extra measure. Great stuff btw. All vacs are new and snug.

      Gv125 hardtail bobber

    • #4644
      ♠️ MARCEL
      Administrator
      • Topics: 38
      • Replies: 381
      Joined:
      Jun 29, 2020
      @mf448kxn6
      North UK
      GTR
      Points: 4,334

      The CV Carb hangs upside as downdraft its not just Korea who designed the bike to need the box but also the carb itself will always run better with the box. Even pods dont work.  So if were you i would make a box 😉 then put a foam filter across the top. 650cc hyo GT is a bit like that. Box with a panel filter on top under the tank.

      90 92.5 is safe. The bike is baffled so well done for that as pipes matter a lot . It doesnt need all gases escaping or it runs slowish.

      Needle on slide being furthest away from carb (richer) is good.  Stock is middle groove.

       

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

    • #4646
      Swin
      Member
      • Topics: 2
      • Replies: 3
      Joined:
      Jun 29, 2020
      @swinny
      Middlesbrough, uk
      Gv125
      Points: 31

      The CV Carb hangs upside as downdraft its not just Korea who designed the bike to need the box but also the carb itself will always run better with the box. Even pods dont work. So if were you i would make a box 😉 then put a foam filter across the top. 650cc hyo GT is a bit like that. Box with a panel filter on top under the tank. 90 92.5 is safe. The bike is baffled so well done for that as pipes matter a lot . It doesnt need all gases escaping or it runs slowish. Needle on slide being furthest away from carb (richer) is good. Stock is middle groove.

      I thought needle top groove shuts the needle making it leaner? And bottom notch lifting the needle making it rich? 🤔

      Gv125 hardtail bobber

    • #4648
      ♠️ MARCEL
      Administrator
      • Topics: 38
      • Replies: 381
      Joined:
      Jun 29, 2020
      @mf448kxn6
      North UK
      GTR
      Points: 4,334

      Check this out for further clarity sorry i didnt paste it before. I was getting out of bed 😆

      [Tutorial] How to adjust Carb Slide Needle (Tuning) – Hyosung GV & GT 125/250

       

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

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