Non running puzzle?

[pepperami]

So Project Scrappy Hyosung 125 is still ongoing .

So the problem is to do with it not continuing to run after being started?
New valves, new guides, new cam-chains & guides/tensioners, new carb rubbers, new plugs , good compression, fuel, spark,etc.

The engine will start and sounds good (quiet & no unusual rattles).
It will run for about a minute or two and then just cuts out????

Any ideas oh mighty and wise BCF.
please
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I am the sum total of my own existence, what went before makes me who I am now!

[xX-Alex-Xx]

Vacuum in the fuel tank from a blocked vent? Will it run with the filler cap open?
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DILLIGAF

[Kawasaki Jimbo]

Fuel pump? I recently snipped the fuel pump wire on the carb’d ZX6R without realising (I was trimming a cable tie) and it did the same.

[pepperami]

[pepperami]

[pepperami]

Fck fckity fcky !
I’ve just found one issue that might not be helping the situation!

The choke cable and choke handlebar lever are missing
The bike has no choke to start from cold.
This might not be the problem, but it might be a contributing factor.
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I am the sum total of my own existence, what went before makes me who I am now!

[WD Forte]

If it will start from cold I doubt its the choke cable

As you assume we're all intimately familiar with the Gt125 and dont
bother adding a feckin pic, I had to look it up.

anyway seeing the layout and given the symptoms, the answer is pretty obvious I reckon

here's a pic
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bikers smell of wee

[stinkwheel]

Sticking floats/needle valves? After it's conked out, try cracking the float bowl drains to see if there's fuel in them.

I had similar on a KLE500 and it turned out to be ethanol damage on the needles causing therm to go furry and stick in their seats. The float bowls were filling but only very slowly. Fixed by replacing them with modern viton tipped needles.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[blurredman]

How many years have you been working on this bike?
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CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (bored to 295cc) - 38k, 1990 MZ ETZ251 - 49k, 1979 Suzuki TS185ER - 9k, 1973 MZ ES250/2 - 17k.

[bikenut]

Does it loose spark, this is when those red neon plug caps come in so handy...

If it does loose spark, why ?

A dmm will now come in handy along with a wiring diagram...
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nuts about bikes

[pepperami]

[pepperami]

[Robby]

Assuming it's carbed, it's running for about the time a bike will run on what's in the float bowls. So do what Stinkwheel said.

[blurredman]

If it's running okay when cold but without the choke cable connected, then perhaps it's running rich? What do the sparkies look like?
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (bored to 295cc) - 38k, 1990 MZ ETZ251 - 49k, 1979 Suzuki TS185ER - 9k, 1973 MZ ES250/2 - 17k.

[pepperami]

[MCN]

TLDR.

Choke thing is a thing.

If it starts, runs and stops, then that is zakly what a choke would do.

Too rich mixture will stall the engine.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Jim Mc]

[Andy Perrett]

Sounds like fuel starvation.

Pull the petrol line off the carb and check the flow. Is it a dribble or a flow?
If the fuel tap is vacuum operated (has a second thinner hose going to the carb or inlet manifold), take it off carb end and suck on it to create fuel flow.

Sounds like if left it fills the float bowl, then can’t refill it fast enough to meet demand. If tap flow to carb is good, probably time to take the carb float bowl off and clean out the carb.

[Nobby the Bastard]

Fuck me ragged. You posted something about bikes.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[stinkwheel]

[Andy Perrett]

[Nobby the Bastard]

[stinkwheel]

[Andy Perrett]

[Easy-X]

Had some poor running on the Kwacker. Pulled the fuel lines and eyeballed the flow from the pipes. All looked good

In the end we dropped the bowls with the the carbs in place. One carb had a lot more flow pissing out than its partner and it turned out one of the T-pieces from the fuel pipe was blocked on one side.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter