VF500 32mm carb question

I recently acquired an early 84 VF500F2 in bits with a blown head gasket and knackered inlet cams. Its been disassembled for 20 years! After review its all reasonably fixable and the plastics and tank are perfect so its up for rebuild. I started with the carbs which took 3 runs through the ultrasonic bath to clear the airways. On reassembly I noticed carb 1 and 4 have 2 drillings just below the inlet manifold, whereas carb 2 and 3 have only 1. I would expect these to be blanked off , and most are, but carbs 1 and 4 both have a drilling that is not!
See pics. Now my question is, has the ultrasonic bath somehow loosened the blanking which is now lost, or is this normal?

 

I will dig a set out tonite or this weekend. I highly suspect it is normal.

Is that the pilot screw side?

A quick test (probably still disassembled) would be to blow some compressed air in and see if you hear/feel come out anywhere.

 

Well...they sure do look nice and clean - so kudos for that part, mate!

 

Not pilot screw side, and blow down test didn’t yield anything. I have since pulled my 30mm carbs of a later F2 and its the same! So none the wiser on its use.

 

It is likely the entry point for passage machining that is plugged in a different location / manner.

 

I agree on that.
On another point on these carbs is the crazy air vent. That vent into the plenum. When I fuel tested, no.2 and 3 carb shut offs failed and petrol overflowed into the plenum and then into the carbs. I read about this but never really appreciated how dreadful it it is. Had the carbs beed mounted I would have flooded petrol into the engine. I have now modified the breather pipes to vent into a pipe to the rear of the carbs like the 30mm 86 carbs do, and plugged the holes in the plenum.

 

That is the right move. 85 are vented to atmosphere too. However, your jetting could now be very rich, as venting to the plenum really fucks with jetting requirements. You should consider going to 1985 jetting specs as a starting point. They went from 108 ('84) to 90 ('85) for the same size carbs.

The 1984 VF1000F is vented to the plenum and has wildly larger jets than the VF1000R.

 

Thanks. Ill check the jetting. It'll be a while before this one gets fired though.