i have a 05 yfz 450 i just did the cam mod put a no toil air filter in it and i put a fmf jet kit in it and removed the airbox lid. it said for my mods and elevation to use the fmf needle on the 5th goove with the washer they gave me. then remove stock main jet put in the adapter and to use the dj138 main jet for 3000-6000 feet. im at 4500 so thats what i used. then it says run the fuel mixture screw all the way in and out 2.5 turns so i did. and it seems to run really rich so i put the dj 142 in for elevations under 3000 feet. it did the same thing so i put the dj 134 one in and it still does the same thing. should i turn the fuel mixture screw back in a little bit? thanks for all your help

 

somebody please help i cant figure it out. i do not have much experience with jetting. any info or advice with be very helpfull and aprectiated... thanks again

 

It seems to run rich where? Wide open, at idle. You need to give a little more info about how it's running before anyone can give you advise.

 

its runnin i think really rich in the lower mid rmp its fine if your just barly putting around and if your up in the higher revs. it sputters alot and if you rev it up a little black stuff comes out of the exhaust.
thanks for you help

 

If you are using dyno jets get rid of them...they are junk. Go to your local dealer and pick up a few. 45 & 48 pilot and 168, 170, 172, 175 main...you probably won't even need all those. Make sure you get the jets for the kehnin carb

 

im using an fmf jet kit.. should i go get those gets try those and then keep the fmf needle in there? and if so on what groove it told me groove 5?
thanks

 

I don't know too much about the fmf jet kit...i'm still using the stock needle, but i've heard a lot of people saying to use the yz needle aka. nvcq needle. But you said dj138 and dj140....thats why i think the fmf kit consists of dyno jets....which are junk. I would go and buy the individual jets. You could spend $20 on jets, i think the yz needle is less than $10 and those things should save you a lot of headache. I would also suggest going to other websites and doing a search on jetting...there are tons of threads on jetting and i know one of the threads could get you close to where you need to be. Just my .02

 

if i get the yz needle what groove should i use?
thanks for your help

 

3-4 clip....up is richer and down is leaner, just so you know...And another thing, don't mess with the fuel mixture screw until you get it pretty close to being jetted correctly...it'll mess you all up

 

thanks a bunch i really aprectiate it