2001 Honda TRX 400ex

[aztecgwynn]

My dad has a 2001 honda 400ex so I bought him a curtis sparks pipe for it. He does not want the air box lid removed so I am still going to jet it to what sparks web site indicates.
My question to the forum is where is the air needle or adjuster and the needle is it adjustable or does it have one slot cut into it nonadjustable. Curtis Sparks jetting info has it at 155 main, 42 pilot, and needle stock location I just want to be prepared when working on a bike that I have never worked on.
And also we plan on using this bike only at Glamis thanks.

[CSR400EX]

they actually reccomend a 45 pilot with their exhaust the last time i looked. but the needle is located in the slide of the carb. just take the top cover off the carb. you will see the slide and a arm that raises and lowers it. look down into the slide and locate the two screws that hold down the arm to the slide. take them out and remove the part that connects the slide and the arm. the needle is under this. use a pair of needle nose to take the needle out. it has a clip on it and 5 positions. if its stock, it should be in the third clip.

hope this helps

[aztecgwynn]

One more thing where is the air screw on the carb and what kind of tool do I need to adjust it.

[bansheemorphine]

The A/F screw is on the bottom of the carb it is just a flat head, i found it neary impossible to adjust while on the bike unless i loosened the carb up and turned it sideways the starter is in the way when it is in the normal position.

[F-16Guy]

That jetting sounds pretty close, which doesn't surprise me coming from Sparks. The idle mixture screw is a little tricky to get to, but I've found that the screwdriver in the tool kit actually works pretty well. If you need a little more clearance, just pop the crankcase breather hose off and lay a rag over the opening so nothing gets in there while you're adjusting the screw.

As far as mods go, you should also look into a filter to compliment the pipe. The stock filter cage has a very restrictive metal baffle, so an aftermarket filter such as a Uni or K&N would be a big help. You may also look into one of the modified airbox lids if your dad doesn't want to run without one. It has a cutout in the top with a filter element to allow air in but keep dirt out.