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3x3 hole? 2003 kfx400

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:ride::thumbsup: have a few questions. not used to kfx. all stock. I rejetted to 137.5 and removed snorkle. Still doesn't want to run right. acts like it runs out of gas in 3d gear. after that even less I pulled the carb and checked float 13mm Is this a normal thing with these bikes What is this 3x3 hole I read about? Need help!

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how did you get the idea for a 137.5 main jet?

take the entire lid off and go with a 160 main jet.

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ok, should I put a outerwear in place of the cover. what about the fuel screw and low speed jet. Won't these change without the cover. I thought from reading these posts that 160 would be too rich

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An EHS Racing lid could be what you want and the #160 MJ would be a good start too.

EHS Racing

The mixture screw at the front of the carb could be set at around 2.5 to 3 turns out.

Depends on altitude and other mods as well though (exhaust ?).

I have no lid,TwinAir filter,stock exhaust (modded), #155 MJ, 3 turns out on the screw with a stock needle and it runs well at sea level if thats any help ?

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when you said stock exhaust {modded} what did you mean Is this something to do at home and how.. looking for more pep without a lot of money outlay.

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I dont really recommend this as all it does really is make it louder but it does rev out a little quicker though.

Just get a hole saw about 1.5" and drill out the rear chamber and voila !

I made the alloy cap at work and screwed it over the existing muffler.

You can also cut off the stock spark arrestor assembly instead and use that for an endcap if you want.

But really you should just save up about $450 and get a proper system.

Picture012.jpg

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thanks for the info. I think I will not be doing that, we have to keep the noise down I will just do the jets and cover for now and then pick up a quieter exhaust later

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