I've played a few games as the Yor and as a custom race using the Yor tech tree. Lack of econ buildings is a perpetual complaint - and a valid one - but I like it overall. Let's see . . .
First, I'm sure somebody will pop in to say "just trade someone for the econ techs", so let's get that out of the way. If you really want to become an economic juggernaut, there's nothing the Yor can do to beat a few planets full of Galactic Stock Exchanges. If you're a purist or just need to get by until you can trade up, there are a few things you can do.
To start, boost your econ and morale abilities with your bonus points. Higher econ means more money and higher morale means higher taxes which means, of course, more money. You could also boost population growth, which will expand your tax base more quickly. If you boost research, you'll be able to get the Yor econ boosting techs more quickly.
For political, there's the Federalists for the 20% econ or the Technologists for the 20% research. If you go 20% bonus research plus Technologists, you'll get +40% research and a fast track to better economy.
About that technology, the Yor have a unique group of techs for boosting economy, called Efficiency Studies. Each tech level grants a global econ bonus (5%,10%,10%,10%,10%) Get your research machine running and plow through a couple levels to bolster the economy. There's also the techs that boost population growth, and you know about the charging stalks for higher morale and population.
Last thing that comes to mind off hand is the Efficiency Center, a one per planet building that gives a 25% econ bonus. The technology prereq is Efficiency Studies 3. Sure, you can't spam it like the stock exchange, but I'll build one on each planet until I don't need them anymore - say I trade for the stock exchanges.
Having said all this, I'll add that even these measures don't make me an economic giant. They do, however, allow me to afford my expansion and generate a decent surplus until I can get the techs I need to make some economic planets.
Hope this helps a bit.
PS - I just remembered the Recruiting Center. Research Space Militarization, or the equivalent Yor tech, and put one on every planet for +10% econ and +20% population growth. These are the engine of your growth, and I make Space Mil a priority tech early on just for that reason.