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KDX Jetting too lean?

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On my '06 KDX200, i'm changing the jetting from stock, to 45 pilot, 155 main, and i'm at about 300ft. elevation and live in NH. How do I tell if the jetting is too lean? I don't want to blow the engine or create faster wear, because of inadiquate lubrication. What are the signs of too lean jetting, on a KDX? And where is the air screw? And what is the clip position? And if it is running too lean and not smoking AT ALL, can i screw in the air screw and it will have more gas/oil and less air and run richer? Please help, thanks! AND is the stock needle in the middle position, when the bike rolled out of the factory? I havent touched it, so will it be in the middle, as of now? and how do I get to the needle, to adjust the clip position?

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I doubt that the jetting on a stock 06 KDX200 would ever be too lean if anything it would be a bit too rich. My 05 KDX220 was way rich out of the box.

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You won't be too lean with those jets. If you want to make sure, you can do plug chops and check the color of the plug insulator. The air screw is on the side of the carb facing you. There is a big plastic screw, that is the idle adjustment screw. The air screw is the small brass one. Adjusting that will only affect the first 1/8 of throttle position, not the whole spectrum. The stock needle has 4 positions (grooves). Stock is most likely 3rd groove down. You should try moving the clip up one position to 2nd. If you get a lean "bog" somewhere around mid throttle, put it back to 3rd. To get to the needle remove carb, unscrew top cap, remove throttle cable, then unscrew the little cylidrical nut thing and the needle will come out. handle it gently, you don't want to bend it.

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On my '06 KDX200, i'm changing the jetting from stock, to 45 pilot, 155 main
That will put you right in the ball park for jetting with a stock bike, but you also want to install an 1173 needle.

If you really want the bike to run the way it should, you need to open up the air box and ditch the stock boat-anchor-exhaust for an FMF K32 or K35 pipe, or a Pro Circuit pipe.

is the bike supposed to smoke from the exhaust at all? because it doesn't.
A properly jetted two-stroke with a reasonablt-quality pre-mix oil will not smoke once the engine is up to operating temperature, nor will it make spooge.

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That will put you right in the ball park for jetting with a stock bike, but you also want to install an 1173 needle.

If you really want the bike to run the way it should, you need to open up the air box and ditch the stock boat-anchor-exhaust for an FMF K32 or K35 pipe, or a Pro Circuit pipe.

A properly jetted two-stroke with a reasonablt-quality pre-mix oil will not smoke once the engine is up to operating temperature, nor will it make spooge.

Is my needle now #1174? Whats the difference? I have taken the snorkel out of the lid and drilled six ½" holes in the lid. I have a FMF Gnarly pipe and a FMF PowerCore2 silencer, so I just need to get this jetting right. And I use synthetic oil in my bike, mixed at 32:1.

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is the bike supposed to smoke from the exhaust at all? because it doesn't.

Make sure the carb is sealrd good in the reed side boot. An air leak there will make it too lean

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ok, so i lower the needle to make it leaner? and i higher it to make it richer? Whats the difference in changing the clip position and changing jets?

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ok, so i lower the needle to make it leaner? and i higher it to make it richer? Whats the difference in changing the clip position and changing jets?

Lower needle/Raise clip = leaner

Raise needle/lower clip = richer

Pilot jet = controls 1/8 to 1/4 throttle

Needle = controls 1/4 to 3/4 throttle

Main jet = controls 3/4 to full throttle

If you are lean or rich in any one (or more) of these circuits, then that circuit needs to be adjusted accordingly

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Is my needle now #1174? Whats the difference?
Yes, stock is 1174. The 1173 is a half-clip leaner. And it makes a world of difference in the way the bike runs.

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The thing is, i dont think the bike should be any leaner. Yesterday, all I did was install the FMF Gnarly and FMF Powercore2 and install a 45/155 jetting combo and i think its about as lean as it should be. Like i said, i dont want to burn up my engine. But does that 1173 needle allow more gas in, making for a richer mixture?

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No, the 1173 is leaner, not richer. And unless you are riding below sea level on a 100 degree day, you are in no danger of being anywhere near lean with those jets and the 1173 needle. The 1173 will really help perk up the throttle response in the half-throttle area.

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Right here, on justKDX, it says:

"The straight section – has the most effect between 1/8 and 1/4 throttle where the transition is made between the pilot/slow circuit to the main circuit. If this range is too rich a needle with a leaner/ larger straight section diameter may be required. If the range is too lean a needle with a richer/smaller straight section diameter may be required."

Which says the opposite of what you are saying. And the way JustKDX explained it makes more sense to me because richer means more fuel/less air. If the needle is smaller, it would let more fuel around the outside of it, causing a richer mixture. I am not trying to argue and i appreciate the help. I am just trying to get my bike dialed in. Thanks!

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k, thanks! and does 3/4 of the throttle literaly mean if you divided the rotation measurement of the twist throttle by 4, its the 3rd section?

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When your needle is too lean you will feel the bike "holding back" as you roll into the throttle. Sometimes you will hear the engine idle hold higher, then slowly drop to normal after you come to a stop. I select my main jet using needle clip position #3, then fine tune the clip position if necessary. You want your spark plug insulator to be a deep, dry chocolate brown.

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okay, thanks. That also helps a lot. And how do I get the needle out!? I took it out, but i didnt know if the cable holder screwed out or what...It has a hex on it, so i figured it did, but i dont want to try and end up ruining it. Thanks

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