new jets

[Grim Reefer]

I have a 00 400 ex with a supertrapp slip on added. If I add a k&n filter and power lid, would i have to change jets? If so what size would be right?

[hondamanex400]

yes because when you add more air, and dont change the jet, it will run lean. so w/ those mods i'd say you need a DJ-175 below 3000 feet.

[jeremy_283]

dynojet makes a good kit and it tells you wat jets to use in the instructions but some people are against it ..... their instructions dont apply for other brands of jets. i would say 160 keihn jet but search the forums..... the brand of slipon or pipe usually is not going to matter becuz they all give them same power increase usually just verying just give or take 1 horsepower....... do a search dont worry about the brand of pipe

[2004exrider]

First off welcome to the site. My suggestion is screw paying for a $40^ kit of jets when you will only use a coulpe of them. If its already jetted you'll only need to go up 1 or 2 main jet sizes. Stock is a 148, so if you pull it out and thats stamped on it then go up to a close dealer and pick up about three Keihin jets (they'll be stamped with a "k"). I'd grab a 155, 160, 165 that should be a good place to start, you shouldnt need to go any richer.

If you really want to fine tune the jetting you should put in a #42 pilot jet, and turn your air/fuel screw out to 2.5 turns (stock is 2.25). That should fill in any flat spots in your carb. You shouldn't have to mess with the needle position any but if you need to richen that up a little put the clip on the second notch from the bottom of it (stock it the 3rd notch). You shall now be set on your carb:macho

Jimmy

[Grim Reefer]

Thnx for the help!

[ccd]

Here is some info I gathered from this site when I did mine. It really helped!My set-up is UNI filter,lid on,punched out factory muffler(1.5"hole)w/4" super trap disks(6), 155 main,factory pilot,2.5 turns out on fuel screw,needle factory position,=tan plug and runs like a hellion.

Mine- piped, with a 1 by 3 inch hole with screen in air lid. 162 Main. 1 size up on pilot, and 2 clips from being the richest on my needle = tan plug.

160 keihin mainjet
needle clip in the 4th position from the top (3rd is stock)
42 pilot jet
2.2.5-2.5 turns out from lightly seated on the fuel screw (with the 42 pilot jet in place)

i would say that a 165 would be waaaay too rich for the slip-on and your location. try out a 155 to start and then go up or down from there. when i had a white bros slip on and k&n filter lid on, i didnt change my jetting at all and i was running a tad rich. with all the stuff on my quad now, im only running a 160 main, 40 pilot, clip on the 3rd notch, and it runs perfect. my elevation is approx 2,000 ft.

Is a slip on all your running? No other mods? If you are only running a slip on a 165 is too rich on the main. I would suggest a 152 or 155 main. Also move your needle back up to stock posistion.

forget the jet kit. buy individual keihin jets. you should be able to get them from your local dealer or C&D racing can also get them. i would get a keihin 155 mainjet. run the stock keihin B44A needle in the 3rd clip position from the top. run a kehin 42 pilot jet. start at 2.5 turns out from lightly seated on the fuel screw

if you run a jet kit, all of this will change besides the pilot jet and the fuel screw. the mainjets are measured differently so a 155 keihin will NOT be the same as a 155 dynojet (mainjets in the kit). also, you will get a different needle too. thus, the clip position may be different.

i would get the individual keihin jets that i mentioned earlier. if your dealer is lost you have two options:
1: tell them the mainjet you need is a 13 series. tell them the pilot jet you need is a 21 series. that should help answer questions

i never changed my pilot jet ever,i used to run an HMF slip-on with stock pilot and a 155 main,2 1/2 turns out on the air screw and it ran like a bat out of he**.i also ran a UNI filter.I dont think anyone is neglecting on helping you but one of the best features here on atvriders.com is the search option at the bottom....just my 2 cents.