Help with Vader 125cc grom clone pilot jet tuning

Discussion in 'Chinese Mini's' started by Chad03, Jun 3, 2020.

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  1. Jun 3, 2020 #1

    Chad03

    Chad03

    Chad03

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    Hello everyone!! I have a Vader 125cc (Grom clone) and I currently installed a 141cc TBolt big bore kit in it along with the YX140 piranha camshaft. I also have a slip on exhaust and a mikuni VM22 ( not a real one a Chinese one ) with a UNI air filter on it. I’m trying to get the jetting down the main has a 130 in it takes a mikuni jet. The pilot jet is a Keihin 38. It’s been running a little rough at idle it’ll bounce between rpms and sometimes if I’m sitting at a red light the RPMS will drop kinda low and when I give it gas to take off it’ll stall out. If I’m cruising at around 25 it’ll cut out a little bit but if I give it more gas it’ll go away. I haven’t messed with the needle height on the clip at all. I pulled the spark plug and it was black and smelled like gas it wasn’t wet or anything like that. I looked at my fuel/air screw and it was out 2.5 turns. Should I try to turn that screw in to try to lean it out or do I get smaller/bigger pilot jets. I’m not to familiar when it comes to the jetting part of the bike. I live in a little town in WV and the elevation here is 696. Not really sure how this comes into play but figured I’d add that. Any help/advice would be greatly appreciated I’m lost on what to do.
     
  2. Jun 23, 2020 #2

    Permafrost77

    Permafrost77

    Permafrost77

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    For your motor that is a large pilot jet,second screwing the air/fuel out will lean out the lower the amount of fuel by allowing more air in, try turning it out to 3 and see of that helps is my best guess, hppe this helps
     

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