Need some help with my bike

[RANGER]

Hello everyone,I'm new here and also kinda/sorta new to dirtbikes so dont laugh at my stupid questions please lol.

Ok I have a 97 YZ 125 and I can't figure out this problem with it. The kid I bought it off of never maintained this bike once I don't think. It's keeps fouling plugs all the time and bogs in first, second and then runs awsome in 3rd and so on. I was told might be to much fuel (floats sticking or something like that) so I took the carb all apart, cleaned it, adjusted the air screw acording to what the Yamaha dealer said and it seems to run better but still fouls the plug and bogs alittle in the same gears. I have to run a NGK BR7ES just to have fun for a few hours and I think this plug is alittle hot to be running in my bike since it calls for a 9 I believe but I pulled the plug and it seems to be burning good. I was also told to move my needle in the carb so I took the top of the carb off and I can't figure out how to get the needle out to move it. The carb is a Mikuni TMX, I red somewhere on the net that the needle is not adjustable but all the pics I see shows they are with that clip that moves up and down. Whats up with that I have no clue.

Well I think thats all for now. Dirtbiking is a blast but when the bike runs the the way it does and fouling plugs it gets to ya quick. I quit smoking to save money but now I spending the money on plugs lol. PLEASE HELP.

[MX86]

welcome to the forum

tell me a little about this carb

is everything adjusted to spec?

is the any add-ons or bolt on perfomance items?
when's the last time you looked at the reeds?
what size pilot/main in the carb?

[RANGER]

I think everything is adjusted to specs, I turned the air screw all the way in and then 1-1/4 out other than that I havent messed with nothing else on the carb other than cleaning it. I didnt get a manual with the bike so I'm just going off what the local Yamaha tells me. From what the kid that I bought it off of said the topend was just rebuilt before I got it.

It does have aftermarket reeds and no I have never looked at em. Also has a afternarket silencer.

The pilot/main jet I have no idea what size they are. Hopefully I will have time to rip it apart again tomarrow to look and let you know.

Is the needle adjustable on these carbs?

[Joelt250r]

i bet u either need a diff pilot jet or you just need to rid it and adjust the air screw more 1 1/4 turns from the whole way in seems like usually thats not enough air and would be running rich fouling plugs then after 1st and 2nd you start using the main jet once u get on it and it clears up right so i'd tinker with the air screw a little more and ya check the reeds maybe ones a hair cracked or something or maybe a possible air leak

[MX86]

i'm taking bets on that either

i'm thinking it's either carberation or reeds...

[RANGER]

Well I didnt have time to rip it apart yet, hopefully monday now. I will check everything you guys said to check. I hope it's not the reeds cause there brandnew when I bought the bike. I agree it might be the wrong jet in it. My buddy has some pilot jets he said I could use but there for a different make of carb, I hope they work.

What would you suggest for the air screw, how many turns out?

Yes it clears right up after 2nd gear. 3rd and 4th have major power, I wish 1st and 2nd was like that. If I can not slove this problem I'm just gonna bite the bullet and buy a new carb. What would be a good carb?

[MX86]

keihin pwk

[RANGER]

Ok I pulled the carb off again and checked the reeds, there good. I looked on the pilot and main jet and theres no numbers or nothing on them to tell me what they are. So how am I supose to know what jets to use?

And again how do I get the Jet Needle out?

[Joelt250r]

undo the cable inside the the thing that holds the needle man

[RANGER]

Easier said than done. I tried, it must be broken er something cause it will not come out. I am almost ready to smash that carb into little peices.