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KX100 jetting

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Hello,

I am putting a full FMF exhaust on a 2011 KX100 and I assume I am going to have to jet the carb. I have never done anything carb related, but it is time to learn I guess! The Head pipe will be a FMF Fatty pipe, Gold series and the silencer will be a power core 2. The bike is brand new and has about 2 or three hours on it. I have ran about 3 tanks of gas and I am mixing Motul 2t 800 at 40:1. All my two strokes seem to run good at this ratio with the Motul. So what do I need to do? What jet kit do I buy and how to go about it? I assume it is pretty easy, but need a hand getting started. This bike is only used for Enduro style racing. Thanks for any help!

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Find a road or place where you can top the bike out and get it up to full operating temperature.

With a fresh plug, get the bike going in 5th gear and hold it pinned for 15-20 seconds.

Pull in the clutch, hit the kill button and coast to a dead-engine stop

Pull the plug and the insulator should be medium brown. If you have stock jetting it will probably be black or dark brown, which means you need a smaller main jet. If it's white or very light brown you need a larger main jet.

Don't make changes more than 2 jet sizes at a time and don't make any other changes to the bike between tests. Always use the same fuel (non-ethanol if you can find it). You will need to re-jet for large altitude, temperature or fuel changes.

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Find a road or place where you can top the bike out and get it up to full operating temperature.

With a fresh plug, get the bike going in 5th gear and hold it pinned for 15-20 seconds.

Pull in the clutch, hit the kill button and coast to a dead-engine stop

Pull the plug and the insulator should be medium brown. If you have stock jetting it will probably be black or dark brown, which means you need a smaller main jet. If it's white or very light brown you need a larger main jet.

Don't make changes more than 2 jet sizes at a time and don't make any other changes to the bike between tests. Always use the same fuel (non-ethanol if you can find it). You will need to re-jet for large altitude, temperature or fuel changes.

Thanks for your advise!

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Anyone know how to find the stock jetting #'s from the factory on a KX100?

I have looked through the book, called the dealer and searched around and I have had no luck! It is tough to find anything on this bike because it is a 2011! I have been having problems getting parts and info! I cannot wait till the 2012's come out :thumbsup:

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Went two up on the main jet to #140 and a half a turn on the air screw and it is shredding. Left the pilot stock.

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FMF web site gives specs

put vforce reeds on it

They don't have the specs yet for the 2011. I did call and they game #s to go off till the full testing is in!

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