1500 pre crossflow single Weber.
Running well until going above 4500rpm, after 10-15 seconds seems to be suddenly out of fuel. Dip the clutch and it returns to a weak idle failing to rev.
Have checked jets are clear. Floats set correctly. New fuel pump, filter and fuel lines between filter and carb.
(New plugs, points, coil and leads)
Am usually quite good at diagnosing issues but am getting frustrated with this one!
Any thoughts?