I have a Yamaha XJ700X Maxim It will start fine and idle briefly but when I try to give it gas with the throttle it dies. I have cleaned carbs and resynced them but still no luck. Could this be a airflow issue? If so what would be the solution?

I would take the carburetors and have a professional clean, check, and set them... tell him that you rebuilt the carbs yourself.....

I'm going to guess that "pit ####" meant petcock :-) and yes they do "go bad" in a number of ways. There is a diaphragm inside which can crack over time. There is also a diaphragm return spring which may break (I've seen only one like that though). But most often, the use of fuel with ethanol in it will cause the breakdown of the plunger seal. When that happens, the petcock "leaks".... not externally but internally. The Maxim-X has a vacuum operated petcock which is supposed to only provide fuel to the carbs when set to PRI (prime) or when set to ON while the engine is running. When the engine is off, there should be no flow of fuel. But the damaged plunger seal allows fuel to flow from the gas tank to the carbs at all times, even when the engine isn't running. When you combine that leak with a leaky float valve, the result is usually a crankcase full of gasoline - clearly not good. If you'd like to know all there is to know about the XJ700X / XJ750X petcock, visit the following page on the Maximum Maxim-X web site:
Maximum MAXIM Resource for 1985 86 Yamaha 700 750 Maxim Models XJ700X...
There are also some helpful tips for rebuilding the petcock here:
http://www.maxim-x.com/pix/petcock/maxim-x_petcock_repair_tricks.txt
...with supporting pictures here:
Index of pix petcock
Hope that helps.

running rich is the problem
you tune for idle not high rpm
indicates a needle and seat problem or incorrect float height adjustment
for it to remain at such high rpm after acceleration indicates that the throttle cable is missing a return spring, needs adjustment or is jamming in the outer case

Try to give it throttle as soon as it starts, hold it about half until the engine runs at a high rpm. Then keep doing that until it idles fine. You might have to adjust the idle and mixture screws. Good Luck!!

It sounds to me like your main jet or high speed circuits could be plugged up in the carb(s) or you could have water in the fuel. If you are reasonably mechanically inclined, I would suggest removing the carbs and giving them a good cleaning. You might want to give it a fresh set of plugs and a new air and fuel filter while you are at it.

You'll need to disassemble your carbs and manually clean the jets, and ensure that if you have CV-type carbs, you can see all the needle holders rising when you roll on the throttle.

Actually, they're not Hitachi carbs. Since you have a 1985 "Maxim-X", the model number is actually XJ700XN. The XJ700 does indeed have Hitachi carbs but your bike, the XJ700XN Maxim-X has BS33 Mikuni carbs.

Careful with the model number, the XJ700 and the XJ700X are entirely different bikes.

By the way, if you want more answers about your Maxim-X, feel free to visit the "Maximum Maxim-X" web site at www.maxim-x.com and the lesser known FTP site for the Maximum Maxim-X web site at www.maxim-x.com/pix

HAP

You are getting enough fuel. ck for trash in your carbs