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400 EX jetting
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Posted by: quadrider00

I got a 400ex with a HMF Full system, Twin Air pro flow kit, and a few holes drilled in the airbox lid. the HMF guy sayd i should run stock pj and a 200 mj but i thought dat is way rich..What jetting should i run?!?!?!?

Posted by: 04EXdude

No man, thats way off! What I would try is;
#40 pilot jet
air/fuel screw at 2.5 turns
raise the needle one notch (lower the clip to #4 slot)
start with a #160 main jet

It should run good but you might have to fine tune.

Posted by: Kilabanshee

Yeah a 155-160 main jet should be good for you. Some air/fuel screw vairy alot between different pipes so you will have to find which setting you like best. I had my clip on the needle on the 3rd notch with a 42 pilot jet with the choke removed. This seemed to work great with my yoshi full exhaust, k&n, and holes in the airbox. With the choke removed starting in winter seemed alot easyer as long as the battery always had a full charge.

Posted by: jiggaman2401

Does anyone have any tips to getting to the needle to move the clip? IS there a way to get the cylinder out then remove those small screws at the bottom.. I have a hard time getting to them and dont want them to strip!

Posted by: 04EXdude

I spray WD-40 on all the screws, it seems to help break them loose without stripping the heads.

Posted by: jiggaman2401

Hmm Ill have to give that a shot!

Posted by: bansheex

Buy a set of duck bill pliers from sears.If they look like they are going to strip use the pliers, works every time.