The gist of the matter is that it only makes sense to fly a bike into Venezuela if you're going to take advantage, i.e. tour around Venezuela (where I have not been, but I'm headed there currently and it sounds like a worthy destination). But if you're also planning to transit Colombia, Ecuador, Peru, Bolivia, Chile and Argentina (all also entirely worthy), you're not going to have time to see most of what's on offer, and you're going to pile on a lot of road mileage to no apparent end. Unless piling on miles is what you like to do, of course, in which case never mind.
If you're planning to actually see and do stuff, you might as well start culling right now, because it's not any easier once you're in place and don't have any time to do what you'd hoped. Culling might reasonably take the form of flying into Bogata to start....or Lima....or Santiago....or even B.A., which would give you a nice two month circular trip with plenty to keep you busy.
None of it is out of the question, of course. I spent two months, more or less, between Bogata and Ushuaia. But I only did this by skipping another month's worth of sightseeing along the way, which I picked up on my return journey north towards Buenos Aires. And I've now spent another month and some since leaving B.A., much of which has involved seeing stuff you probably don't want to miss....and I'm still skipping half of what I wish I had time for. It's a big continent.
The reason I asked about your route is that you are, like everyone else, planning to take the route which does indeed have lots to see and do. If you said you'd be coming directly through Brazil, which is shorter and generally less appealing to motorcyclists, your plan would sound more realistic.
(packing to leave Salvador, Brazil)
Please remit: US$0.02