The first question is if you rotated the carb for easier access with the throttle hookup or adjustment needle access. If so, your pulse hole that operates the fuel pump in the carburetor might not be lining up. Some carb/manifold combos you can rotate the carb 180 degrees and the pulse hole still gets a pulse, and others you cannot rotate without further modifications.

Next is to start from scratch and review your fuel system. The pump in the carb is very sensitive to air leaks, and will not pump fuel if there is an air leak in your fuel system. You do not have to use a primer bulb, but you DO have to be sure the fuel line is connected to the proper fuel inlet port. The inlet port is usually the one closest to the cast aluminum cover with one big screw in it on the carb. The other fuel port must be closed off.

You can also try richening the mixture screws a bit, because when you take off the air cleaner, and/or provide a more free breathing exhaust, the engine will lean out from it's original setting. You have to open the needles a bit to compensate. I would say open them about 1/2 to 3/4 turn and try again.

Lastly, if the engine sat around for a while before you mounted it on a plane and tried to fire it up, the diaphragms in the carb may have gone bad. I have had them go bad in as little as a month with some fuels. It is usually the diaphragm under the cover with the four screws, (regulator) that goes bad. That diaphragm has to be very supple. If it is the least bit stiff, replace it.

Let us know how it goes,
AV8TOR