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don't kill me.... jetting?


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hey all, I'm about to do the 3x3 and jet my 09 400s, and don't know what jetting to do since the weather here in south florida is cooling off a little lately. I'm doing and extended fuel screw as well. i know that theres a calculator/chart that tells you the jetting but i can't seem to find it. can anyone tell me a jet and needle setting to start with? I've never done jetting on a carb so I'm a little lost  :bonk:

 

Off to the auto parts store for a drill bit and a 30mm socket so i can change my gearing while I'm at it! :ride:

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I have the jd jet kit. I have it on 25 pilot 155 main, blue needle 4th clip, 2.5 turns on the mixture screw,but it bogs when I accelerate, and doesn't reach full rpms. I'm at sea level, temps range from 65-90. Should I go to the 3rd clip now? It starts and idles fine and has no decel pop at all whatsoever.

Thanks very much!

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Not trying to be a smart ass,but I'd call JD for recommendations. I've had a few of their kits and they usually come with instructions with a few circumstantial starting points. They are friendly to deal with and guarantee to get you jetted properly if bought from them.

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It's an 09 400s with 7300 miles.

3x3 extended fuel screw and jd as of today with a tip mod and stock air filter. I went by what I saw online from other people. It's seems to me like it's too rich on the needle. I've never done jetting or carb adjustments so everything is new to me

The confusion I'm having is based mostly on the needle as that it's more towards 60-70 here lately but the altitude is low so I'm not sure what needle to use

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22.5 pilot with extended idle screw is the way to go. Whether or not that is the cause of your problem is another matter. I have an aftermarket exhaust and even when corked, the bike runs better than with stock exhaust. If you can shell out for a E model header it might help.

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Hmmm, you should be in the ball park??? At this point id suspect a fuel delivery problem or float height. Is the vacuum line to the petcock in good condition?? Pinch's, tears, connected? Run the bike on prime and see what happens...

Possible air leak???

Is the plastic baffle in the right place?? Connected?

Edited by matty86suk
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Sounds like needle tuning to me. You say it's great off the start...(pilot jet is good,) then it gets sluggish and surging, hard to tell from the Internet, but from your description I'd say your a bit rich on the needle. The JD needles are basically half stepped between blue and red.

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having uncorked and rejetted a few bikes I rely on the Dynojet kit.  Worked well in my XR650L although I did intstall a fatter pilot that did not come in the kit, but it is a different bike.

 

my 2014 DRZ recently uncorked with the airbox mod, yoshimura RS2 exhaust (full system) and a dynojet kit runs perfectly! I followed the instructions explicitedly and had no problems. Also used the extended fuel screw.

 

I used a JD jet kit on a CRF450X I had with a FMF slip on and air box mods and it still ran lean.... 

 

Just me but I prefer DYNOJET

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I think that it's partly the weather here. Hot and humid, just doesn't feel hot to me. I'd imagine it'll run like a top tomorrow morning when I head to work at 5:15 (I should really go to sleep) and it's nice and "chilly" out

I may step down to a 145 and go to blue needle 4th clip to see what it does for me

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