Help as quick as possible

[gratzracing24]

Ok i kno this shouldnt be in this forum but please dont move this becuase i need help as quick as i can...ok well i have a 300ex with a pro circut pipe and a k&n air filter...when i bought it the guy said it was never jetted and about 2 months ago it started like back firing real bad and i bought jets but havent had time to jet it and me and my friend were screwing with it and tehre was a 122 in it and hte closet i have is a 135 and we put that in and were letting it run...when u would push the gas quick it would back fire but its still not as bad as it was before...anyone know what the problem would be?

[bansheeguy77]

Originally posted by gratzracing24
Ok i kno this shouldnt be in this forum but please dont move this becuase i need help as quick as i can...ok well i have a 300ex with a pro circut pipe and a k&n air filter...when i bought it the guy said it was never jetted and about 2 months ago it started like back firing real bad and i bought jets but havent had time to jet it and me and my friend were screwing with it and tehre was a 122 in it and hte closet i have is a 135 and we put that in and were letting it run...when u would push the gas quick it would back fire but its still not as bad as it was before...anyone know what the problem would be?

still sounds like jetting. maybe bump it up some more. altho im far from a jetting expert. my 400 used to do that too when it was cold, but when it was warmed up it was fine

[Stevie-D]

my 400 used to be a ****** in the winter to get started. after i learned how to jet it it was fine though.

[EXRIDER400KFX]

dont really know that much about jetting. but that sounds like it would still be your jetting if it's still back firing.

[gratzracing24]

well it was doin this in the summer too...i put the 122 back in and im gonna go get liek a 130 tomorrow and see if that helps...thanks 4 the help everyone

[Dumontexrider]

it sounds like your too rich. Take your airbox lid off and see if it runs any better. Taking your air box lid off will lean out your bike. if it runs better, go down 1 jet sizes. if it runs worse, go up 1. after everytime you rejet, put the lid back on and see if it runs better

[Scott-300ex]

sounds rich, if i were you i would just move my needle down:macho

[bulkdriverlp]

if the guy said its never been jetted, the stock size is 122main. check ur needle position, theres 5 slots, the middle position is stock, youll need to move the clip down 1 slot for the pipe. the main should be around the 132. if not try the lid thing. check ur plug

[Scott-300ex]

to lower the needle you have to move the clip up

to raise the needle lower the clip

i think you need to lower the needle, so move the clip up

[bulkdriverlp]

Originally posted by Scott-300ex
to lower the needle you have to move the clip up

to raise the needle lower the clip

i think you need to lower the needle, so move the clip up i dont know much about it, but i just had my carb all apart and jetted it! cant start it cause waiting on slip on. you are exactly right when you talk about the clip, but lowering the needle will restrict gas flow and raising the needle will let more gas flow right? why would he wanna go leaner than stock when he added a slip on? like i say im not dissagreeing with ya im just wondering myself im no jetting expert.

[Scott-300ex]

yeah, but apparently he moved his jet up a big amount, 122 to a 135

he said

"and tehre was a 122 in it and hte closet i have is a 135 and we put that in"

so i just think he might be runnin rich cause i don't think your supposed to go that big of a difference, but i see what your sayin

he'll just have to try different stuff

[gratzracing24]

Yea im not very good with engines and stuff...but we cleaned the 122 and put it back in and it was backfiring worse than with the 135 and after we ran it with the 135 for a few we took the carb back apart and gas was just pouring out of it i was goin to get see if i could find anyother jets but it was snowing and my mom wouldnt let me leave....i have 135 140 145 150 155 those size jets and a 40 piolit which we did mess with

[exrider360]

take the air box lid off wamr it up real good its def the jetting im running like a 128 with my full whitebrothers and uni filter nd it runs pretty good.

[gratzracing24]

I just tryed it without the airbox on and the 122 in it and it sounded like it was almost sucking for air...my air filter is dirty could that be it? i dont really kno im just thinking about stuff umm im gonna go try and get some more jets today so ill see what happens

[gratzracing24]

well i bought a 130 so ill see how that works and some handlebars for the fun of it