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View Full Version : yet another jetting question by a newbie



08-29-2001, 01:23 PM
I just got my k&n jet kit today and have started my first attempt at jetting my 400ex. My only mods are a k&n filter with outerwear and a WB slip on exhaust. Airbox lid is on with no holes drilled (yet). I followed the stage 2 directions that came with the kit and redid the needle valve to the third notch and put the washer on top of the e-clip. I jetted to a 170 and that didn't seem to be right so I worked my way down to a 155. I seem to be having the same problem with every size. The quad will idle fine but when I rev it up into the higher rpm's it seems to start cutting out. I noticed when I changed the jet it didnt seem to be seated in the bowl straight. I did not cross thread it or anything it just seems to be sitting in there crooked. Is it supposed to be seated crooked? What is causing it to cutout at high rpm's? My stock jet was a 148 and I've tried all the larger ones with no luck. Can someone with a similiar setup tell me what their settings are. Sorry this was so long!!

Razorback
08-29-2001, 01:32 PM
Sounds like you are rich. With no air box mod (no lid, holes, etc.) you need to just run stock jetting or possibly one size up. You simply can't get enough air with the box closed up. I have the same setup as you, but with a 2 1/2 hold in my lid and 160 main jet, second clip from the bottom on the needle and 42 pilot. It runs great with this setup. You will be very pleased if you get some more air into your system. To test it out, take the lid off and go for a ride and see if it improves (be aware this may cause you to run lean, but it should act different than it is now, which should lead you to the answer you are wanting).

Also, my main jet is off-center as yours is, so I don't think it is a problem. Good luck.

Here is a picture of what Gabe (one of the most knowledgable people on this board) did to his air box lid. I did a similar thing after seeing his and it works great. If water gets in, it just slides under the filter and out the hole (have to take off the plug). http://home.earthlink.net/~gellett/airbox_mods.htm

01ytrx400ex
08-29-2001, 01:53 PM
Make sure to run it under a load or you could be hitting the rev-limiter.