Help motor dies when i go above 80% throttle

[roozbeh]

This is making my head scratch guys...

My bike can go 50% throttle for more than an hour.
However when I go above 80% throttle for more than 20 seconds then the engine dies off... I am 100% sure it is not supposed to do that lol.

So right after it die this time I saw that the plastic tube attached to gas tank is filled mostly with air and not gas and there is gas in the tank...
Any solutions for this guys?


cheers,
---------------------------------------------------------
Engine Details:
-66cc engine
-nt carb

 

[headtrama]

Make sure the tank is venting .

 

[wayne z]

Gas cap not venting or restricted tank filter. Try pulling the fuel line off at the carb and check for a good flow.

 

[roozbeh]

Normally I close the gas cap tight. So are you saying it should be loose?
And the air in the plastic tube is able to move fairly easy.

 

[wayne z]

No, Im saying that a lot of the kit gas caps don't vent properly, and if you loosen the cap and it starts running right then that proves that the cap is the problem.
The fix is to drill a small hole(1/16) on the underside of the cap, right next to the gasket.

Sometimes it's normal for an air bubble to be trapped in the clear hose. That's normal and has no effect as long as the fuel flow is good.

 

[dcf11367]

I had the same problem once. check to make sure the motor mount nuts are tight. engine vibration at high rpm's caused bubbles in my air line. stopped when I cranked it down tight.