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hellshot00
10-04-2010, 06:28 PM
Well i have a slip on big gun and now have a K&n air filter with outterwear cover to run without an airbox lid and i know ima have to jet it but my question is. I have no clue how to jet. I understand it in a basic sense but idk if i have the confidence to not screw something up any help would be muchly appreciated
PaRedneckRiders
10-04-2010, 06:44 PM
Originally posted by hellshot00
Well i have a slip on big gun and now have a K&n air filter with outterwear cover to run without an airbox lid and i know ima have to jet it but my question is. I have no clue how to jet. I understand it in a basic sense but idk if i have the confidence to not screw something up any help would be muchly appreciated
not hard at all, easy way to do it is just pull the tank and front plastic off then the heat sheild then loosen the to clamps (one on each side of the carb)

drain the bowel and pull off the bowel (four bolts and move the idle set screw)

and change the main and the pilot jets

(on the 99-04 the main was a 148 and pilot was a 38 if im not mistakin)
I would bump the main up to a 155 and the pilot to a 42 then not sure about the fuel/air screw (man its been a while since ive worked on a 400 carb)

But ya i would say 155 and 42 would be a base line and then go from there, u might have to change depending on elevation and riding temps
hellshot00
10-04-2010, 07:47 PM
from wat ive been reading its all trial and error? so im guessing alot of aggravating tinkering around with the fuel/air screw and main and pilot?
honda400ex2003
10-04-2010, 07:56 PM
155 main, 42 pilot, leave the needle, and go to about 2.5 turns out on the f/a that should get you close. lots of trial and error without a sniffer to check it for sure. take the bowl off the bottom to get to both at the same time, for quick main changes you can take a 1/4" socket and a 17mm wrench and change the main using the quick access hole on the bottom of the bowl. steve
hellshot00
10-04-2010, 08:18 PM
thanks steve i guess il be wingin it haha
honda400ex2003
10-04-2010, 08:23 PM
start with the suggestions. steve
hellshot00
10-04-2010, 08:36 PM
will do and hope to lord it isnt to far off but what jets should i buy i was thinkin either the FMF or the dyno
honda400ex2003
10-04-2010, 09:37 PM
just get a 155, 158, 160, 162 from your dealer along with the pilot in 42 and you will be good to go. you can save a bit of money on a kit which is about worthless anyway lol. if your dealer doesnt use them yamaha jets are close enough to be able to use. series 16 i think is the pilot series also. take them out and take them with you so you can match them up correctly. steve
hellshot00
10-04-2010, 10:17 PM
i never realized how much carburetor illiterate i am but thank you steve your the man
10-05-2010, 12:06 AM
Originally posted by hellshot00
Well i have a slip on big gun and now have a K&n air filter with outterwear cover to run without an airbox lid and i know ima have to jet it but my question is. I have no clue how to jet. I understand it in a basic sense but idk if i have the confidence to not screw something up any help would be muchly appreciated

PUT DA LIDD BACK ON !!!!
hellshot00
10-05-2010, 01:29 PM
why
honda400ex2003
10-05-2010, 01:33 PM
ignore his post... its all caps anyway. no need to yell it let alone say it. :rolleyes: steve
hellshot00
10-05-2010, 03:12 PM
ban hammer is sounding mighty nice but i noticed that rockymountainatv sales main and pilot jets specific to ur machine i think im just gonna order a 155 158 160 and a 162 then the 42 pilot from there its 3.21 for the pilot and 2.24 for the mains what do you think?
honda400ex2003
10-05-2010, 05:39 PM
sounds pretty cheap to me. another good place to get them is jets r us. com

steve
hellshot00
10-07-2010, 02:42 PM
so i called the local dealer today and he has the jets but he said to maybe start with a 152 or a 153 (i dont remember which)
honda400ex2003
10-07-2010, 06:25 PM
it would be a 152 there isnt a 153. be my guest as to what you want to run, it will be close with that too. I just suggested something based on what i have experience with. It could be totally different if you are at higher elevation or warmer temps or something. just do some plug chops to see how it is coming along once you change things. this will indicate how it is doing. steve
hellshot00
10-07-2010, 09:14 PM
i just wasnt sure bout buying another main i think i will stick with the 155
honda400ex2003
10-07-2010, 09:17 PM
its only a few bucks so you might as well get that one too. I have almost every jet from a 160 to a 180 lol in my box. the only one i dont have is a 165 which is the one i want to start using for summer ripping once warmer outside. lol I guess i have one more to get then ill be set. steve