1994 honda magna 750 will not accelerate

SOURCE: Carb removal from 1994 VF750C Honda Magna

You should probably get a service manual.
As I recall: Remove seat, gas tank, side covers and brackets, and plastic things in front corners of frame. Take off rubber intake thingy and slide out air filter cover toward the left side (it's a ***** because of the flap in front). Loosen metal intake housing plate, rotate and remove intake horns being careful not to bend the horns or drop screws down carb throats. Slide plate out.
All four carbs come off as one assembly. There are four rubber tubes connecting it to the engine. Loosen the hose clamps on the tubes and gently pry the carb assembly up. Find safe points on the carbs to pry where you won't break anything, and be gentle. If it hasn't come off before it will take some going from corner to corner till it comes out of the rubber tubes.
You can clean the jets without disassembling the "quad pack".
I put a little oil on the tubes to reassemble. Getting the horns back in is a bit tricky. The plate goes on loose, then they slide into the carbs and rotate as I recall. Good luck

SOURCE: 1997 Honda Magna 750 installed new plugs but still

De-cell popping is usually caused by a lean condition. Sounds like you could use a Dynojet kit.

SOURCE: 2002 HONDA SHADOW ACE 750 CARB

It sounds like you may have or will be jetting your carbs. I did this using the directions with the kit and used the Clyman manual for this bike to show me step by step how to remove the carborator. You will only need to attach 2 of the 4 hoses on your carb. syncronizer. If I remember right, you need to remove the bolt-on cooling fins to expose the engine block. The is a black screw or bolt that you take out and screw the threaded metal adapter of the sync tool. Be careful using the sync tool. Be very light on the throttle or the vacuum in the cylinder will **** in the mercury from the sync tool - not good. The problem you are stating on idle & backing off sometimes happens when the carbs are running rich (too much fuel) Hope that gets you in the right direction.

SOURCE: Honda, 80 elite with 41

First make sure that the bystarter is indeed functional: look at it, it should move when powered. Simple test to confirm that: remove the screws that hold the unit into the carb, and lift the choke slightly out of the carb body while cranking the engine : if it runs, then the carb is ok, choke is not. If necessary remove the air filter, put your hand in front of the carburetor to choke it even more and then start the motor.
If the engine dies even now then the problem is in the carburetor: either the idle is badly adjusted or the level in the bowl is too low.