What would cause this ???

GoldenMotor.com

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
24
38
Ridin' inSane Diego, CA.
It really does sound like the petcock (in tank) fuel filter is clogged. Very common problem from expirience.

I just remove them and put a quality in-line filter on instead. A cheap yet effective fix....

The cheap chinese tanks that come with the kits come with everything except gasoline (petrol) in them :D