Carby Tuning Problems!

[avenger_125]

I Need a bit of help trying to tune my carby. I just bought a Pod air filter and got my main jet drilled from 95 to 100 to increase air and fuel flow, but now with it all installed cant tune it properly. I have got it to the stage where it idles and runs great through most of the rev range and has a sweet bottom end. The only thing is when im topping out in any gear, the engine doesnt run smoothly, it like misses when its firing or something. But it is only at high revs. Is this a tuning problem that i can fix from the mixture screw or the eclip on the needle? or is it something worse?
also it is a mikuni carb(not sure what size) on a 1125cc ducar

 

[pitmaster]

who drilled your jet?

when you start drilling jets your just asking for problems,

did you do a spark plug chop, to see if you actually needed the jet changed?

when the throttle is opened past 3/4 the eclip is fully out, so its not doing anything, so adjusting that wont change anything full throttle,

sounds to me its that jet causing your problems, cause you say its fine everywhere else in the rev range,

 

[avenger_125]

i had the jet done at epping motorcycles. the only thing i realy want to know is if this means that the mixture us too rich or too lean? i had the filter on before i drilled the jet and i found that it kept bogging down when you accelerated. so i had the jet redrilled to allow for more fuel to even out the mix. now im stuck trying to work out if my problem is bcos my mixture is too lean or too rich

 

[daniel40]

check your sparkplug black its rich white its lean it needs to be a coffee colour to be right.

 

[avenger_125]

its completely black. so which wy do i go on the main jet mixture screw? in or out?

 

[daniel40]

ive got no idea all i no is your bike is running rich.

 

[avenger_125]

hahaha. thanks neway, lol. Well i no its a stupid question but im sure someone knwos which way to turn the screw?

 

[Quick-Prox]

my carbys at epping bikes atm there drilling 1m too i pick it up in 1hour howmuch did they charge u?

 

[daniel40]

its free to drill it out i got mine done there, i thought you had a 105 pj.

 

[avenger_125]

Yeh it was free but i just took them my main jet n thats it. Anyone know what direction to turn the main jet screw to make it leaner? and also 1/4 turns or 1/2 turns?

 

[Quick-Prox]

its free to drill it out i got mine done there, i thought you had a 105 pj.

na that was for teh 125cc the 105...

 

[daniel40]

oh ok then

 

[avenger_125]

come on guys, some one has to know? i want to work this out rather than having to go back to stock! neone know which way to go?

 

[daniel40]

maybe try screwing it in and see what happens but do it slowly and make sure u check the colour of your sparkplug and i think your surpose to tune it when its warm, but becareful.

 

[Divy]

if your bike runs good between idle 1/3 throttle dont touch your air/fuel screw

your saying that the plug is black which means its running rich an you said that 3/4 to wot (wide open throttle) that its not running right

when its not running right from 3/4 to wot that means you dont have the right main jet, you have a 100 main jet on it now an its still rich so i belive you need to go for a bigger main jet, the bigger main jet will lean it out a bit more an should get it riding better on wot
im not sure what size you should get but i would get a 102.5 an a 105 main jet an try them both

 

[avenger_125]

if your bike runs good between idle 1/3 throttle dont touch your air/fuel screw

your saying that the plug is black which means its running rich an you said that 3/4 to wot (wide open throttle) that its not running right

when its not running right from 3/4 to wot that means you dont have the right main jet, you have a 100 main jet on it now an its still rich so i belive you need to go for a bigger main jet, the bigger main jet will lean it out a bit more an should get it riding better on wot
im not sure what size you should get but i would get a 102.5 an a 105 main jet an try them both

I thort that when it is running rich ur getting too much fuel and not enough air? wuldnt getting a bigger jet just make it worse because it would allow more fuel in?

 

[Quick-Prox]

i just got back from there he adjusted my air/fuel screw. so i gotta put it on the bike now cbf doing it tho its to cold lolz

 

[avenger_125]

maybe try screwing it in and see what happens but do it slowly and make sure u check the colour of your sparkplug and i think your surpose to tune it when its warm, but becareful.

The B*&CH of a place where the screw is makes it hard to do when the engine is warm or running cos it gets Farken HOTT!!! anyone got suggestions on how to adjust it without burning urself?

(ive already tried to make the screwdriver tip on the end of a bendy hose but its frustrating to get in)

 

[avenger_125]

i just got back from there he adjusted my air/fuel screw. so i gotta put it on the bike now cbf doing it tho its to cold lolz

How much did it cost u for the jeting and tune up?

 

[Quick-Prox]

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