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!

 

It might run better warm?

 

I let it warm up good first, then closed the choke, and it acted the same!

 

Anyone else have any other suggestions? Please!

 

Before you do any adjusting you need to know that the carb is clean. If the wheeler has been sitting for months and the carb is dirty it will be next to impossible to tune. Which could be why its runs better with the choke on.
What worked well for me was when the f/a screw was backed out 3.25 turns or more it was time to go up 1 size on the main jet. Reset the f/a screw to 2.25 out and start adjusting again.
While you have the carb apart put in 40 pilot. It really does help with the cold starts.