high idle,backfire from the air box?

[ECHILD]

the other day i got a fmf power core 4 slip on dirt cheap.so today i put it on my quad,now it will pop and run for a half a sec but not run,i'm not sure what my jetting is but i'm pretty sure its rich.(black spark plug).i have a 2003 with a KnN AIR FILTER.what should my jetting be around?
what ajustments can i make to get it running so i have a stating point?
thanks in advanced

[08ex4]

sounds to me like your getting to much fuel throw a leaner jet in it and see what happens

[08ex4]

was your buddies quad a 400 ex and if so was it stock compression and bore also are you both running the same fuel

[ECHILD]

i took the other carb off and put mine back on. mine was jetted rich,i think,now it wont even start.

[08ex4]

what jets are you running?

[08ex4]

your gonna have to find out what jets your running regardless youe gonna have to go leaner with that filter get a new plug too

[08ex4]

im not sure how familiar you are with tuning and all this but if i were you i would get it running and let it alone no more mods you can see what i have done to mine and i havent noticed much of a difference in it for the money ive spent if you want more power find some retard on craigslist that wil trade you your bike for a 450r my buddy just traded his 05 400ex for a sick 450r the guy said he wanted something that was more ridable for his 12 year old son

[08ex4]

can you keep it running by giving it gas if so turn your idle up

[Miami_Vice454]

if you would have bought a header too your bike would be faster. instead you decided to spend that money on a timing key when in fact you should have gotten a full system. you make the gains from the header. i definitely noticed a difference in mine when i put my exhaust on

[ECHILD]

ok i havent turned the idle up or anything(it started snowing a little so i quit for today.)and i have bearly any money into my bike,i got a carb and nice slip on for 40 bux.would you of turned it down:eek2:

[Miami_Vice454]

oh ok yea i would have taken it for 40 bucks, but i was actually talkin to 08ex4.

[ECHILD]

ok i pulled apart the carb.the pilot is a 38 and the main is a 148.is that to rich?

[katch26]

thats stock......I would imagine you need to go bigger....lid or no lid?

[rob_990]

id put a 42 pilot in it if its already snowing.it makes it so much easier to start in the winter.go up a few sizes on the main too.get a few of them a couple sizes apart then buy more jets and fine tune it

[ECHILD]

i dont ride when its cold much.i've broke my fingers and they get so stiff i cant move them.lol,,so my jets are stock?and yes i have my lid on..

[ECHILD]

ok i called fmf today.they said to use a 40 pilot and 152 main with a foam filter,so i am gunna go back to a uni and try those jets.i dont really like a k-n-n anyway..

[Miami_Vice454]

K&N* K-N-N lmao

[ECHILD]

ok K&N you get the point,lol

[Miami_Vice454]

lol i didnt put that to bash you evrybody mispells things on this including myself, i just thought it was funny

[ECHILD]

yeah no prob bro.i always do that,like internet ebonics!lol

[ECHILD]

i ended up putting a 42 pilot in and a 152 main.it seems to run great.but i did not have a chance to ride for a half hour.to get my spark plug color.do i have to adjust the pilot screw?if so do i just make it sound good at idle? would the 42 be ok in the summer too?j/w

[Ryan'07400ex]

What did you guys say about when the carb like kicked back/ backfires and shakes the whole intake? TO lean or to rich?

[ECHILD]

i think that means lean but do some more research,i'm no pro..

[Ryan'07400ex]

Originally posted by ECHILD
i think that means lean but do some more research,i'm no pro..

Well I had stock jets in but then I added a Uni filter and took about an 1/8 of an inch off of both headers. I left the air box lid on. I then put in a 42 pilot and 152 main. I also have a sparks 6* key and a ballance slip on.... What im saying is I thought this would be more rich if anything :confused: but it doesn't run exactly right now. the carb bickfires and it stumble with quick acceleration.
I'm not even an amatuer at jetting haha

[ECHILD]

your prolly right,i dont know much i'm new to jetting.i used to just pay the shop but i dont want to give my money away if i can get it right.ya know

[ECHILD]

ok so i got to check my plug and its black but i have it jetted a little rich for the cold season.its pretty responsive i still have to get my idle tuned in a little better tho.dose this sound good