whic jet kit is best?? K&N, dynojet, other??

[Pur Pony]

I was wondering who makes the best jet kit for my 400ex??
Does K&N make there own kit or does dynojet make the kit for K&N?- i though i read that somewhere?

thanks much

[400exJOE]

the dynojet is sold by K&N.

[Pur Pony]

correct- thats what i thought- but K&N puts their name on the dynojet kit- right??

[400exBro]

Yes!

[Pur Pony]

thanks all

[400exRacerX]

I just bought khien jets from my honda dealer, its alot cheaper and they don't need the adapter like the dyno kit does.

[Pur Pony]

what about an adapter?? whats that for and does it come with the jet kit????







also does the jet kit only come with a bunch of MAIN jets??? does it come with any of the other jets needed...




I was just going to buy jets- but im not sure what to use- no one really has a straight answer- not even my honda dealer-

I am running a yoshimura race pipe/header, k&n, vented airbox.....

[Atomic83]

The kit will come with an adapter, main jets, and a needle and clip. The main jet screws into the adapter and the adapter screws into the carb (no big deal).

If i were you I would just go buy the jets. since your setup is similer to mine i would recommend about a 160mj. but buy a smaller size and a bigger size just in case.

[Pur Pony]

Atomic83-

your setup is almost exactly like yours- except i have a header also-

so yours runs good on a 160mj?

do i have to change the slow jet or slow air jet? the other jet.... I was told to run the slow jet around 40??

stock is 38 on the slow jet...and 110 on the slow air jet.

where is your needle set at?? i was told #2 on the needle groove-

thanks

[Atomic83]

I run a #155 in mine, but I think i need a #158, but it doesn't come in the kit. I have a offroad slip on, but you have the full race pipe. Thats why i think your jetting should be a little higher than mine. The needle is in the 3rd position. I think i need to bump up the pilot jet to a #40 because when I start up after a few days of not riding, it is real hard to start and it backfires bad. I'm not sure it will help though.

Hope this helps.

If you don't use a kit, then get a #40 pilot jet, 2 1/2 turns out on the mixture screw, #158 main jet, and put the needle clip in the third groove from the top. :square

[Atomic83]

He may need a little larger than a #158 judging from my setup...

Yea maybe. Most think that a big jet means big power but the opposite is generally the case. Seems to me that a 155 would be a minimum and most stock motors can't really handle more than a 160. Of course elevation, fuel mixture/additives, and even barametric pressure/temperature can make a big difference.
I try to start in the middle of the recommendations, especially if there are more than one aftermarket parts. For example: WB recommended a #165 jet with their cam, big gun recommended a #155 jet with my exhaust setup. I started with a #160 and ended up with a #158. This may or may not work with other machines in other places, even with the same mods. But it would be a good baseline to start from. :D

[Pur Pony]

ok- well i am still deciding what i am going to do- lol... i have not taken a plug reading yet- but i have not ridden much yet either- after thanksgiving. I talked to a guy today that has a 2002 400ex with my exact set-up in MASS. He said that he went and messed around with his and every jet he tried made the machine run worst- he is back to the stock jetting- beats me-

[Atomic83]

just go buy you a few jets and be done with it.. I told you what my setup was and how it runs. Go get you a #158, #160, and maybe a #162. One of those will work, but you never know untill you try.

[Taco]

Originally posted by Atomic83
He may need a little larger than a #158 judging from my setup...

But dont you have the dynojet kit?? the dynojet numbers do not cross reference with the keihln jets.

[Pur Pony]

Tacostrk- so are you saying that the non dynojet 158 jets are different then the dynojet 158?????

I got prices on jets and they are $8-$10 bucks a piece- and if i have to get a 155-158-160 +40... I may as well just get a jet kit and be done with it- that way i get the needle and everything

[Atomic83]

that is a little steep for jets... my dealer has them for like 3.50

I hear that the dynojets are a little different than the keihln jets, but not that big a difference.

[Taco]

Originally posted by Pur Pony
Tacostrk- so are you saying that the non dynojet 158 jets are different then the dynojet 158?????

I got prices on jets and they are $8-$10 bucks a piece- and if i have to get a 155-158-160 +40... I may as well just get a jet kit and be done with it- that way i get the needle and everything
yes the dynojet jets have a differnt taper so they meter fuel a lil bit differently. I would shop around for your jets i usually pick up jets for $3-4 and you are not limited like you are with the dynojet kit. And why do you need a needle? The stock needle has adjustment also.

[Poncho]

I've heard nothing but good things fron k/n.:D

[Pur Pony]

can anyone give me a website where i can order jets cheap- around $3 or so.... ???

[400exRacerX]

You guys can't tell him a exact setup to run, then he goes and sets it up and it runs like crap...... Your jetting all depends on your elevation. You could have two identical 400ex's will all the same mods and have one in colorado and one at the jersey shore and the one in colorado will be jetted alot richer. Just put a 155 in, test the plug and go from there.

[Pur Pony]

Well i ended up getting a dynojet jet kit for my 400ex.
I figured I couldnt beat the price of $35.00 shipped to my door. should be here tomorrow or thursday-

A very wise purchase,,you'll have ,,better starting,,better fuel effeciency,,better throttle response,,,,,,just buying a few jets and doin it that way will work,,but using a dynojet kit is the way to go,,,I mean,,that's what they do for a living. They test and meter ways to make a motor run better,,,,that's what your payin for when ya get a jet kit,,,not the few jets and needle you get,,which most people think. YOur paying the salary of a guy wearing a white lab coat that tests, monitors, calculates, and takes notes on how fuel and air mix using dynojet kits,, with particular motors,,,so basically your paying for someone using there brain and a few bucks for some brass and directions. For the non beleivers go out to dynojet or K&N's webpage and read up, heck ya might learn sumtin..:D