Motorcycle Repair: Fuel Tank overflow, hongdou cg125, vapor lock

Question
Hi Chris,

I have a brand new Hongdou Cg125  bike, and it still hasnt been really used yet as it is not registered, but the other day i uncovered it from it shady spot and moved it into the sun, checking it over, after about ten minutes in the sun it started to pour out fuel, the bike was being rocked no and then, i understand the need of the overflow from the fuel tank, but it was only half full, the only thing i can put this down to is the heat from the sun and me rocking the bike everynow and then, it only poured out about half a liter.

If i am right sorry to bother you, otherwise, what do you reckon caused this.

Thanks
Brendan

Answer
Hi Brendan.
 Fuel tanks come with a pressure relief built into the gas cap.  This prevents heat and other factors from building up pressure and forcing the fuel out of the tanf as well as working to allow air into the tank to prevent vapor lock, which would prevent fuel flow from the tank to the carbs.

It is possible that the vent is blocked and pressure is building up causing the fuel to back up through the relief.  Take the bike over to the dealer and have them check it out.  It could be something as simple as a faulty part.

Good luck.
FALCON