<VV> BackFiring through LH Carb

[Bob Gilbert]

Hi,

 

Something odd has just started with my fresh 3.1 build. It will idle happily
all day long and rise smoothly up through 4000 RPM but when I just blip the
throttle , I get backfiring through the driver's side primary carb. All of
the sparking equipment is new; coil,  plugs, wires, Pertronix II etc. The
carbs are fresh from the Carbmeister. I've tried adjusting the static timing
to see if it makes an difference and it doesn't. For now I'm running at 16
BTDC static.

 

I've set the valves cold at half turn past zero leash.

 

Any ideas?

 

Thanks,

Bob