need advice on what could cause this slight engine problem

1st I hope the timing is dialed in decent.
the jetting sounds good, however...even if the vac sec was not opening, it should not fall on it's face, maybe run out of rpm for lack of flow/cfm, but not drop out and fall on it's face.

And how I would tune the vac sec springs...is put the weakest spring in , that should get you a bog when getting into the secondaries..now you just put a stiffer springs in till it doesn't bog, you want to use the spring just before the one that made it bog.

really though....what shooter is on it, whats the number stamped on it?