Bike Wont Fire up 81 Cb750c

[locust17]

Previous owner had pods on it *YES I KNOW WORST THING THAT COULDVE HAPPENED**
Had put bigger 120 jets and ran somewhat lean. I decided to put on the stock airbox to see if it would do any difference although it still had bigger jets and did not fire up anymore. It cranks but won't start. I messed with the air fuel mixture and the little nobs on each carb and nothing. I don't know wether I screwed up the factory setting of each carb nob and the pilot screw.

I had it running this summer with the pods but very lean and never had a chance to mess with it due to school.

[TOOLS1]

Have you checked for spark? You could have knocked a wire loose while changing the airbox.
TOOLS

[shinyribs]

Pods won't affect you at all until the bike gets under heavy loads/ upper rpms. You can get it running and lightly cruising around on pods just fine.

First thing's first:

1- Check for spark. If no spark check

 - fully charged battery. I've seen weak batteries that show decent voltage at rest, but when the starter is engaged they don't have any ''left over'' to fire the ignition system. These bikes' ignition systems rely heavily on a healthy battery.
 - healthy plugs ( not fouled our melted looking)
 - plug boots and wires. you can trim a bit off a wire and screw the plug boot back on to ensure a good connection if one seems loose.
 - coils are getting voltage

2- Check for fuel
 - are the plugs wet?
 - are the accel pump squirters squirting out fuel?
 - float level (non adjustable on these, but a bad float will still sink)
 - faulty/stuck closed needle & seat, aka fuel inlet valves

3- Check for timing
 - Download the FSM off the homepage here and check static timing
 - Double check the correct coil is firing the correct pair of cylinders.

When you look in to timing in the FSM it can seem a little daunting, but it's really very simple. The manual is just very detailed, so it gives the appearance of a lengthy, complicated process. But it ain't bad at all.