Backfiring while cranking engine

Ok so I am very new to trying to adjust timing. I set the valve clearance to specs and now the bike is backfiring when I try to start it. This is on a 1982 Kz440 belt. I really dont know what I'm doing and everything I look up seems like I'm missing a plate. Attached is a picture of what I'm working with. 

Your engine has transistorized ignition and is not adjustable in the way that a points ignition is. You can read about it in the factory service manual. Details are in the supplements at the back for the 1981 model.
kzrider.com/service-manuals

Did the engine run properly before you started the maintenance? If so, I would carefully recheck the valve lash. Valves that are not closing will cause backfire and afterfire.

The bike was not firing on both cylinders even after cleaning carbs, switching spark wires, boots, and plugs so I thought may be it was a valve issue. The valve clearance checked out on both cylinders so I put everything back together and now I have this horrible back fire when cranking the engine. Its on the right side cylinder. Left side is still not firing either. I thought may be I needed to set the crankshaft at a different location to stop the backfiring. I didn't have to adjust any of the valves so now I'm just confused. 

What do you mean by switching the wires? If the wires are backwards you will get the back fire from the raw gas getting ignited on the exhaust stroke.
If only one cylinder is back firing and only one cylinder was not firing after the cleaning then maybe it is still  clogged and that is why you are not getting the back fire on both cylinders.
Try reversing the plug wires.  

By switching, Imeant replacing with new. My bad.

On a twin with a single coil, switching the secondary wires does not matter as they always fire together. It is like 1/2 of a four cylinder ignition system.
If the engine has not run since you got the bike, then there are many more possibilities as there is no telling what some previous owner may have done.
Have you checked the fuel level in the carburetors using the clear tube method?
When you cleaned the carbs, did you take them completely apart and remove the bodies from the rack and soak all the parts in carb cleaner, then carefully insure that all of the tiny passageways are clear?
Did you replace all of the gaskets and orings?
Did you do what is called bench synchronizing before putting the carbs back on he engine?
Are the vacuum ports covered with new rubber caps?
Are the carb holders supple and free of cracks?
Is the air filter box and a clean air filter in place?