throttle valve needle?

[Yz 125eR]

what is the stock throttle valve needle # for a 01 yz 125? 5mv100 carby. its running rich and going through heaps of plugs, was going to move the 'e' clip up and see what happens but wasnt sure if it was the stock needle, as i had just got this bike. I know it has the standard jets and i am using a 40:1 premix ratio. she's fine when im thrashin it but hates it when im puttin around? help!

 

[shane.ballard.nf]

goto yamahaaccy.com and then yamaha oem parts select your year and model then pick carburetor

it will list all the parts, prices and show images
there are several different needles listed but i think stock is
NEEDLE (6BGK9-75)
STD (5MV1)

 

[shane.ballard.nf]

Also i got a random needle put in my yz490J, does the needle make a huge difference? because i can't buy the standard 6F16 needle because they dont make em new anymore i needs to track one down somewhere if i can

i think theres a 6DH4 or something in mine now with the #440 seat

 

[kartstar]

my only experience comes from needles on our CR125 shifter kart engines, but they make a HUGE difference! i ordered one a single letter off, looked up the various tapers and diameters, they didn't vary by much at all - maybe .025" on the length of the center taper and i had ZERO midrange throttle response - it would just miss and sputter from 1/4 throttle to 3/4 throttle. i got the "right" needle from another guy with the same engine builder and it ran like a Caddy...i guess you could try, but the needle is tuned for the flow characteristics of each engine, so you'll have different needles for stock v. highly modded/125 v. 250 with the same carb...

 

[shane.ballard.nf]

well the mods i have is that the engine is bored .020 over, dg exhaust and silencer, uni air filter.

i'm gunna try to find the stock needle for this bike but it's gunna be difficult i needs to buy another 490J i think that has all stock specs, or find a good place to get parts for the yz490's

from my experience driving the bike the way i got it set now theres almost zero revving the bike just gets enuff revs to go through its gears and sometimes the revs wont allow me to do that and i goto fool with the throttle a bit till the bike starts revin a lil.

is it normal to have to move down sizes in the seat or should i beable to get my jetting with stock needle/seat i think u always keep the stock needle in right, but change the jet down or up a size and then tune with the circlip on the needle

i think #440 is not guna cut it, i'm gunna try today with the needle on the leanest setting and see if it makes a difference

 

[Yz 125eR]

cheers shane!

 

[shane.ballard.nf]

LoL

well after using google intensely i found another bike which uses the same needle 6F16, which is unavailable to order for a yz490J it's a 1987 Yamaha YZ 250 T
also i beleave the YZ490K has the same needle
gunna get that today hopefully.

i got #430 seat coming now to

:ride:

w00t

the sooty color on the spark plug is getting lighter with each jet/needle clip tweaking so i think i'm getting closer



Did you get your YZ working better after Yz 125eR?

 

[Yz 125eR]

yep. just kept playin with the carby and seems fine now.