KX100 jetting

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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Help!!

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.

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!

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:

Don't they usually list stock in the generic owner's manual?

It's the easiest way to really know if your main jet is right. Once you've got that you can play with your needle and pilot jet.

Don't they usually list stock in the generic owner's manual?
I found it in the manual, I missed it!

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.

FMF web site gives specs

put vforce reeds on it

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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