People 50 2t revs to full throttle for 30seconds then cuts out

[Crappykymco]

Hi guys im new to the forum and small engines world (prefer my big turbo audi but its not very college campus friendly) any way i have an 08 kymco people 50 that cannot hold full throttle, bike is all stock from what i can tell and will rev to full throttle then acts as if the throttle has been cut even though im holding it wide open and if i continue to hold it open it was sputter all the way out and die. Idles great, get fuel, carb is clean, battery is brand new, spark plug is a bit diry but sparks fine. I believe its an ignition issue am i on the right track? Whats the fix? Thanks for the help guys!

[Stig / Major Tom]

Miles?
How does it run at 85% throttle?
Stig

[tortoise]

believe its an ignition issue

As in no spark when the engine dies?

[eamartin]

How does it run at 85% throttle?
Stig

Yes.  When the symptoms occur, will a little less throttle keep it going or will it still die?  Does it die dead no matter what you do?  If you let it sit for (?), does it start right up and run fine again until full throttle?

[Crappykymco]

At less the half throttle it does fine. Let it run for almost 8 hours yesterday to run it out of gas as it was the same stuff it was stored with. Sat just fine. It i rev and dont hold it open it wont die but it will no longer be able to rev for another 30 seconds. Its has 10000miles


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[eamartin]

One possibility is that it is not getting quite enough gas to keep the bowl full at higher RPM's.  Could be the gas cap vent is not fully open.  Easy enough to test by running with a loose or removed gas cap.  Another possibility is a faulty fuel cock assembly not letting sufficient gas from the tank to the float bowl.  I would test this by bypassing the vacuum activated fuel cock with a line going directly from the fuel tank to the carb (cap the vacuum line if you do this).  Another possibility is that the air cleaner is not letting in sufficient air at higher RPM's.

[Crappykymco]

If fuelling was the problem wouldnt it more likely sputter out, when it cuts it literally seems like the throttle has been snapped shut. And it behaves perfectly up until this happens


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[eamartin]

It would sputter out if you had no more fuel delivered to the bowl (as in empty fuel tank or completely closed petcock).  What I am saying is that fuel is being delivered to the bowl at an insufficient rate - a rate at which the system can keep the bowl full at partial throttle but at full throttle the bowl is not being replenished quickly enough.  By running at lower RPM's for a bit, the system can "catch up".  Of course the problem could be something else entirely.
 I'm just offering one simple-to-check possibility.

[Crappykymco]

Ok. Ill be testing the stator and ignition coil, ill add fuel filter and carb to my list! 


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[Crappykymco]

Done the tests, you were right its definitely a fueling issue. Notice carb pukes fuel. So im assuming a new fuel filter and carb rebuild is in order. Any preferred vendors or decent upgrade options? 


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[eamartin]

"Notice carb pukes fuel."  What does this mean?

[eamartin]

Do you have a stock clean air filter?

[Crappykymco]

Fuel will come out of the carb rather then through at wot. When using the stock air box and filter the box will have a small amount of fuel at the bottom and the lower portion of the filter will be wet with fuel. Im guessing my reeds are worn?


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