Can anyone suggest a good starting point for setting carbs?

[ArronA]

Hi me again! you'll soon be sick of me of you're not already lol

I've been searching google for the past 2 hours trying to find the standard carb settings for the 3tj and there doesn't seem to be any info on it, It seems to be a very popular topic from what i have seen

At the moment my needles clips are on the centre groove of the needles, there are 2 grooves left above the needle clip and 2 grooves left below the needle clip, cylinder 1&4 has needle code 5CEW16 and cylinder 2&3 has needle code 5CKP3

My pilot screws are all at 2.5 turns out

Main jets on cylinder 1&4 are sizes 100 and cylinder 2&3 are 97.5

Pilot jets are 32.5

Carbs fully cleaned and rebuilt with LiteTek seals

The bike from cold first thing in the morning will not idle for at least a minute so i have to hold the throttle open a tad then it's fine, it also seems to be quite tricky to get started but once it's started and warmed up it appears to be sweet, a bit annoying really, i spoke to someone earlier who told me to richen up the mixture a bit and see what happens but i can't imaging it would be that simple, I'm guessing anticlockwise would richen the mixture and clockwise would lean out the mixture ?

I appreciate your time! honestly

[enduro250]

As you have seen below, I am thinking about the same.
The setting of your carbs is depending among others, on your air box, filter and the mounted exhaust.

[ArronA]

As you have seen below, I am thinking about the same.
The setting of your carbs is depending among others, on your air box, filter and the mounted exhaust.

The bike is completely standard other than a scorpion silencer which i want to change over for a standard one if i can find one

[Evilchicken0]

As my comment on the other thread check the Set up manual in the document library of this site.
I think the larger jets should be for the middle two cylinders but check the manual and where the needles should be.
You should be able to start the bike without throttle but using the choke.
The carbs probably need to be balanced

[enduro250]

Based on the Yamaha manual, the outer cylinder have the larger main jet.
Usually the middle two cylinders are running a bit hotter, therefore you use the lager.
No idea why Yamaha uses them in this way, and additional nobody could explain it.
My “dyno man” suggest to use the identical 4 jets.
Anyway, to be sure your carb settings are correct, you have to measure the Lambda value (fuel / air ratio).

[Evilchicken0]

The bigger jets have a different needle as well - it used to be thought the inner cylinders will run hotter than the outer so a slightly richer mixture would be down to cooling them .... but all jets the same (not sure about needles) seems to work just as well.

[enduro250]

sorry, you are right, the diffrence in the needle results in a larger diffrence of the diameter then the main jet.
(in the area of the second angle and below)
I have never seen diffrent needles in my 3 TJs, maybe there were too many people working on them.

[enduro250]

Anyway, if you have a standard setup, use the standard carb setting as starting point.
I guess, they are a bit on the rich side.
You are losing power on the top end or it’s not revving smooth to the limit, if the mixture is not ok
To get an optimized result, measure air / fuel rate (my personal opinion).

[ArronA]

Does anyone know the order of the plastic spacers and the shim type washers that go over the needles? below or above the needle clip ? metal washer on top of the plastic spacer or vice versa ?

[Evilchicken0]

Look on the CSML parts website they have exploded diagrams. I think the needle goes through the plastic washer so the clip sits above it.

Tip: never take all the carbs apart at once, only ever do one at a time