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Discussion Starter #1
Gentle people,

So I have the following problem with my 350 Ipotesi, she starts and about 1 till 2 seconds later the engine stops.
Since she starts, the magneto pick up, spark coils and sparkplugs should be fine otherwise she won’t start in the first place.
Opened up both carburetors and they are clean, fuel lines are not blocked, fuel filters are clean.
When opening up the main fuel valve with the ignition switch fuel is flowing straight away, same as for the reserve valve.

Any suggestions where to look next as I am running out of options:frown2:
 

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I would guess you are losing ignition spark. Have an extra plug handy...start the engine and as soon as it stops (1~2 seconds?) put the spare plug in a plug cap and kick the engine through watching for spark.

OR, get a dynamic spark tester (you can make one) and watch for steady blue strong spark to confirm ignition is functioning.
 

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Discussion Starter #3
Well, i have a clear spark, thing is, when’s the engine stops, I can immediately start the bike again, it will run for 1-2 seconds (accelerate work, it runs on idle as well) and it will stop again. I can basically start the bike as many times as I want, it just stops after maximum 2 seconds...
 

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Float level in carb too low??? Either that or fuel flow through the float needle and seat is too slow. They come in different sizes.
 

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Discussion Starter #5
Fuel circuit is all fine, checked every piece. Have a feeling it is something electric, with earthing or so but not sure where to start looking and how much resistance a wire should have (when checking for cable breaks)
 

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Wires, and their connectors, should have close to zero resistance when checked with a meter for continuity. 1 ohm is about all you should see.

If you continue to get good strong spark even as the engine stops running then you can forget electrics.

The symptom you describe (steady spark but engine dies after a few moments, only to start again and repeat) is exactly what low fuel level in the carburetor float chamber would cause.

Is there a drain screw on the float bowl (I am not sure about your carb)? If you can attach a clear hose to the drain, hold it vertical beside the float bowl and open the drain screw, you can view the fuel level in the carb while running. Typically it should be close to or a few millimeters below the bowl gasket surface.

Low fuel level in the bowl will cause lean running and stalling. Slow fuel flow through the float needle valve will lower float bowl fuel level as the engine runs, quickly refilling once the engine has stopped.
 
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