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Mikuni 26 carb jetting for a 143 klx bigbore

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I have a 143 big bore with

a mikuni 26 carb on it

main jet is a short hex 125

pilot is a really small 3/8 long 15

external filter

middle clip position (don't know the needle #)

tell me what yours is and i'll double check

bike bogs just of idle big time then catches back up and

runs good on the middle and topend

plug is showing rich (black)

wondering if these two jets are even the right types for this carb

I thought mikuni 26's had round mains & longer pilots

if anybody could please post some pictures

of the right jets that would be great

(I can't get pictures to post on thumpertalk, sorry)

help :thumbsup:

oakley37 in nebraska

1100 ft

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Does the carb bolt directly to the intake manifold, or does it slide into a rubber boot and held in place with a hose clamp?

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It it looks like the carb pictured below, it is:

A. A Mikuni-clone carb that is only 22mm.

B. A baseline setting to work from for that carb is:

1.#100 or #105 main jet

2. #17.5 pilot jet

3. jet needle clip in the 3rd or 4th position from the top

4. fuel screw 1-3/4 turns OUT from seated.

C. Because it is a fuel screw, to lean it, you have to turn the screw IN.

Mikuni22mmcarb.jpg

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If it looks like the carb pictured below, it is:

A. The Mikuni VM26-606 spigot mount

B. The stock jetting for that carb out of the box is:

1. #190 main jet

2. #22.5 pilot jet

VM26-606carb-1.jpg

Here is a pic of the jets the two carbs use...

VMjetpics-1.jpg

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thanks for the pictures

The carb looks very much like the

Mikuni VM26-606

and the jets match the pictures

you have for this carb

So that kinda puts me at ease

(right carb, right type of jets)

But I'm way off on the main

I have a 125 in there right now!!!

can this be possible, runs pretty good from

mid-range and to the top

bogs bad off the bottom???

and what should the fuel screw be set at

for a starting point for this carb

Thanks very much 188

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From what I've read in some of the other pitbike forums, most guys with the VM26-606 are using a 155 to 165 main jet (they are available in increments of 5), and I'd have to double-check to see what the recommended pilot jet is.

As far as the baseline setting for the air screw, try putting it at 1-1/2 turns out from seated, to start. Make your turns in 1/4-turn increments, IN to richen the mixture, and OUT to lean it.

I would try going up to a 17.5 or 20 on the pilot jet, for starters, to clear up the low end hesitation from being too lean in the idle/1/4 throttle area.

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