2000 400EX Run problem ~ HELP

[Bandit17]

New to the forum, and looking for help!
I have seen many problems just like mine, but still feel the need to ask!

I have a 2000 Honda 400EX, it has a K&N filter and a Supertrapp IDS2 pipe. The guy I got it from had a 38 pilot, and 165 main, with the mix screw turned out 3 1/2 turns, and the airbox lid off! It ran ok, but didn't idle the way I thought it should. I started experimenting with different jets, and I am right back to where he was. My problem now is, it will not idle unless the choke is opened to the first position (when it's closed, it dies) it also bogs down at about 3/4 throttle (sitting still of course). Something (coincidence maybe) happened during my attempts to tweak the carb. It is back to where it was, and isn't running right!

What did I do? What did I miss? Can anyone help! Of course, I am leaving this evening for a nice long trail riding weekend, and I have a machine that is not right!

Any suggestions? I am desperate now! :confused:

[DragonGunner]

Welcome.....Did you clean the carb with carb cleaner while you had it apart? How does the K&N filter look, when was it cleaned last? Did you turn your air mixture screw a little each way to see if it made a difference? This is what I would do if getting this quad for myself....1. Take the K&N and scrub it in a bucket of hot water with dawn dish soap, rinse with hot water, shake and let dry for the day, then spray with K&N oil. Get a outerwear for it. 2. Tear down carb, every screw and jet and clean. 3. put a 42 pilot and 185 main if your running open air box for starters. set the air mixture screw at 2 turns out and start from there. Once you get it dialed in and later it starts to act up and bog then you know its past time to clean your filter again.

[Bandit17]

Welcome.....Did you clean the carb with carb cleaner while you had it apart? How does the K&N filter look, when was it cleaned last? Did you turn your air mixture screw a little each way to see if it made a difference? This is what I would do if getting this quad for myself....1. Take the K&N and scrub it in a bucket of hot water with dawn dish soap, rinse with hot water, shake and let dry for the day, then spray with K&N oil. Get a outerwear for it. 2. Tear down carb, every screw and jet and clean. 3. put a 42 pilot and 185 main if your running open air box for starters. set the air mixture screw at 2 turns out and start from there. Once you get it dialed in and later it starts to act up and bog then you know its past time to clean your filter again.

I didn't thoroughly clean the carb as it looked pretty clean already! I will clean the filter tonight, and it does have an Outerwear on it already! I turned the air/mix screw in and out a few times trying to get the right settings, I have it set the way Dynojet told me to set it (suggested setting of course, I like your idea better). Thinking maybe I loosened up some dirt somewhere and it found itself in the intake!?!?! :confused:

[Bandit17]

Anyone else have any other suggestions? Please!

[JOHNDOE83]

I didn't thoroughly clean the carb as it looked pretty clean already! I will clean the filter tonight, and it does have an Outerwear on it already! I turned the air/mix screw in and out a few times trying to get the right settings, I have it set the way Dynojet told me to set it (suggested setting of course, I like your idea better). Thinking maybe I loosened up some dirt somewhere and it found itself in the intake!?!?! :confused:

What your describing could be a lean condition and sounds to me like the most likely problem.

But I have a issue with one thing "Dynojet" see a dynojet 165 is really like a kehin size 183.5 www.jetsrus.com

So I would say your describing lean conditions but you might possibly be to rich, without being there I cant really tell you anything.

If it has dynojet GET RID OF IT, buy some nice kehin or oem equivalent jets from www.jetsrus.com, I suggest like draggonguuner said. Get a 42pilot and some main jets in incriments of 5 from 160-200. Put the 42 pilot in and turn the af screw 2 1/2 turns out then follow the main jet tunning method here http://www.jetsrus.com/FAQs/FAQ_rejetting_101_how_to_rejet.htm Your looking for #4 in the jetting procedure about half way down the page. Start with 200 and if it doesnt fully rev out, work your way down in incriments of 5 untill it stops sputtering and fully revs.

Try cleaning it good first...lol.

[DragonGunner]

Don't forget to wash in soap water and rinse the outerwear also. keep us posted how things work out for ya.