Suggestions for getting my scoot running? - Dies when warm

[personality]

It runs pretty well while it is cold*** but then after a few minutes it will just run for a few seconds before bogging out.
Where should I start? Petcock? Is the petcock the same for the 50 & 125? Tank doesn't look look like there is rust inside.
I just bought it, and a few other hands have tried solving this problem, but nothing too in depth I think.

***edit

[tortoise]

Where should I start?

Make a worthwhile research effort, and Google a service manual.

[zombie]

Put a volt meter across the auto choke when you first start the bike. It should read 12-13 volts.
If that passes then pull the choke (careful of the THIN "O" ring), Put the green wire to ground, and the yellow wire to 12v + on the battery. You want to see the pin move outward 4mm or more.

Try this, and let us know.   

[personality]

It's starts easily enough, but it dies when when warm, so the autochoke appears to be doing it's job, the engine just isn't getting enough fuel from the main jet i'd guess.

Do you know if this petcock will work on the 125? I'm going to start with fuel system, i.e. cleaning the tank, replacing the fuel lines and cleaning the carb. 

[tortoise]

going to start with fuel system

Expedient troubleshooting strategy is to disconnect carb inlet fuel line, then apply suction to the petcock vacuum line with a squeezed infant aspirator to verify fuel flow.



Carb cleaning guidelines.

[zombie]

It's starts easily enough, but it dies when when warm, so the autochoke appears to be doing it's job, the engine just isn't getting enough fuel from the main jet i'd guess.

Do you know if this petcock will work on the 125? I'm going to start with fuel system, i.e. cleaning the tank, replacing the fuel lines and cleaning the carb. 

Read my lips... No new Taxes...

The auto choke is open when the bike is cold. IF it is broken it will STAY open, and flood the bike out when it's warm.

Let it sit for 20 minutes, and it fires right up again huh...

Not promising I am right. I can't do my bike whisper over the net. BUT it's where I would begin.
If the petcock were bad it wouldn't start or it would die while riding at 1/2 throttle or so.

Yes the petcocks are not interchangeable. The 50cc is exactly not the same as this one...

http://www.partsforscooters.com/164-93_Bolt-on_FUel_Valve

[zombie]

Expedient troubleshooting strategy is to disconnect carb inlet fuel line, then apply suction to the petcock vacuum line with a squeezed infant aspirator to verify fuel flow.



Carb cleaning guidelines.

Come on tourtise. You could have told him to suck it. Aspirator LOL!!!

[personality]

Expedient troubleshooting strategy is to disconnect carb inlet fuel line, then apply suction to the petcock vacuum line with a squeezed infant aspirator to verify fuel flow.



Carb cleaning guidelines.

hey, thanks. I used that trick to determine the petcock was working fine and to empty the gas tank. There were no particles in the gas I drained or the carb, or jets when I cleaned those so i guess that rules out a fuel issue.
So, I put it all back together and of course now it will start but only run for a minute before dying. I disconnected the autochoke, but that made no difference.

[zombie]

Again we are speaking in different tongues.
If you disconnect the choke it is exactly the same as a broken choke. The symptoms will be the same. The bike will stall in a minute or two.

Test the voltage with the engine running. A simple test light will do. They cost 5 bucks at harbor freight or 2 bucks on Ebay.
Next:
PULL out the choke, and hook it to the battery to verify it is working.

Or check to see if the chain is tight, and the freon is good in the tires.

Sorry to bust your balloons... LONG day.

[personality]

So the choke would fail in the choke   on position gotchya, thanks.
I'll stop the harbor freight this week for the test light this week. Problem is, it is barely running at all now...

[zombie]

Now we speak Chinglish together... It will start running less, and less. The excess fuel does not get burned, and the heat is enough to sort of varnish it onto the spark plug. A little more each time. Fouling...
 Get a new plug while your at it.
Like I said. I'm not 100% sure, just my best shot for now.

Please keep us up to date. It is always helpful for the next guy. A loy of people don't member up.They just pick our brains from the shadows. Damn Zombies...

[personality]

Yeah, spark plugs are definitely on my to buy list. what is the recommendation? NGK CR7HS?

[zombie]

I prefer 8's but it depends on the bike, and climate. 8s are one step colder, and work better for me in Fl.. 7's tend to Ping on acceleration.

I use 9's in my 2t bike.