Covered many times - Carb setup/cutting out

[P.addy]

Hey,

Got my little 140 running. It starts, which is amazing considering I put it together from a box of bits. The engine was done by binge/Pete but every dodgy bit of wiring is mine

Just having issues with it actually running.

I can put the choke on, kick it and it idles, bit fast but assuming thats the choke. If I knock it off it idles a little slower but wants to stall. Touch the throttle at all and its like a killswitch.

Where can I start looking? The pilot jet is the one I've been told to use, 22.5. I'm going nowhere near the main jet yet as I'm not using more than 1/4 throttle anyway until its all MOT'd.

Its a Molkt 26mm carb

[Walloper]

It could be too much fuel killing it or not enough.

Will it run and run and run on choke?
It should start to get lumpy and want to stop as the engine warms up and more of the condensate fuel reaches the combustion chamber to be burned. That will over-rich the mix and give you the stall.

If it is not providing enough fuel with choke off (assuming the choke-on is permitting it to run until the choke is off) then you need to ensure the carburation is correct.
i.e. No air leaks, blockages, correct jets, correct jet setting, correct air cleaner/filter etc.

I haven't a scoobie wot carb should fit that engine but it is important to match the carb to the engine's air-flow.
A 125 carb won't feed a 500 and a 500 won't feed a 125 and that sort-a-thang.
They may provide enough fuel control to start but not enough for smooth/normal running.

I am assuming a lot given the paltry amount of info in your post of course.
And to assume makes an ASS of U and ME.
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Rogerborg]

How have you set your idle mixture screw? All the way in, back it out 2 turns is the default starting position for that carb (on a 125).

And how many Speed Holes have you drilled in the exhaust?
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Walloper]

Not only the concern over your Speed Holes.
I would also take the No. 1 and No. 2 power-bands out and give them a bit of a rub with a wire-brush and then stick them back in too.
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[P.addy]

The carb is the one stated for the engine

Everything is tight, there are no leaks (have only tested with wd40 though)

The air filter is a cut down version of the stock one but still same material and covers the whole inlet and is clamped on.

Assuming I'll need to have a fiddle somewhere but in terms of connecting it up and checking for leaks thats definitely done

Erm, I only had it on choke as its not really been used, it was cold and I'd never run it up before.

If I take off choke I think the idle is too low. Choke idle definitely isnt high enough to be considered choke so I'll turn the idle up and try knocking off choke.

Jet size is 22.5 and 105, but the 105 is too small overall but I'm not using the main jet yet (I assume, I've read its 3/4 throttle and up)
22.5 was what I was told by binge, who runs these engines all the time

[Walloper]

[P.addy]