Here is the inside of the 84 Carb Plenum; The short end of the venting T-Tube pokes in. But note the tube has a Restrictor Orifice in it. or the vacuum in that area could Self-Bias the jetting. I may shrink that Restrictor more. If not then Honda vents to atmosphere. I guess run a hose somewhere gasoline can spill out. Buy not where a wind can pass over the open end, or a vacuum could still occur. Partzilla OnLine does not show the 85 VF1000Ff, since it was not sold in USA, so can't check PNs without going to a Dealer. I have a Carb Bank on Plenum on the shelf, and it has No Holes in the plenum for Venting. I can't place the year on that (came with 2x VF1000F basket cases, along with Quad, Dirt Bike, and Snowmobile parts mixed in). 84 & 85 are Near Identical, with differences in Carb numbers, Glass/Blade Fuses, Paint and Headlight type, and now Carb Venting? Viva La Difference?