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TTR Carburator Jets

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I have been following posts regarding replacing the stock carburator on a 125 TTR with a Mikuni VM26.  I did this and as reported my bike started instantly.  No problems at all with the swap.  The system is running rich though; the spark plug is dark and sooty, but the bike runs well.  I am going to change the air filter to the BBR option to help with air flow.

 

My question is about jetting.  The stock Mikuni VM20 has a 180mm main jet and the Mikuni VM26 I am using has a 190mm main jet.  My confusion relates to the BBR Keihin carb having a 105mm main jet, and many of the TT posts on this subject refer to main jets in that range as well.  I want to lean the mixure some on my bike, but I don't understand jetting well enough I guess.  Any help or education is greatly appreciated.

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Mikuni bases their jetting numbers by flow. You have a baseline for your jetting - too rich. Follow the sticky for confirming your pilot jet setting / adjustment then move to the needle & main jet. Base the evaluations on throttle position.

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Shadrax what year is your 125? Did the vm26 bolt up without any mods? Why did you go with the vm26 instead of the vm24?

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