Does anyone know why I can't beat the elite 4 heres my party and there..

Ok, first of all, raise your arbok's and marowak's level. They are weak compared to the Elite Four's pokemon. The weakest level throughout the entire league is level 52 or 53. They can kill your arbok and marowak- especially Lorelei and a couple of Pokemon belonging to Lance. Raise your 3 legendary birds until they are level 65, or 67. Mine were level 72, but it took forever. Your Charizard's level is perfect. Ok, now for the attacks. For your Marowak, get rid of Focus Energy and teach it dig or something. I like bonemerang, and false swipe (do you know how useful it is in catching pokemon?) and your rage is awesome for long battles- it'll last that long only if you crucially train it. For your arbok, I like it's attacks. It can poisin the foe, heal itself and attack severely- those attacks, I think, are awesome... For your Moltres, get rid of endure and teach it fire blast. Fire spin is good for long battles and flamethrower has high attack AND accuracy. For your Zapdos, get rid of detect and teach it thunderbolt and get rid of drillpeck and teach it thunder. I like the fact you can paralyze the foe, so keep thunderwave. For your Articuno, get rid of mind reader and teach it blizzard, and get rid of Rock Smash (it's weak) and teach if hail (it's good for long battles). And finally, for your charizard, get rid of Cut, and get a heart scale and go to Farllarbor town, go into the Move Tutors house, and reteach it slash. Ok, all in all, this should be your team:

Charizard lv. 75
Blast burn
Overheat
Fly
Slash

Articuno lv. 65
Fly
Ice Beam
Blizzard
Hail

Zapdos lv. 65
Thunderwave
Fly
Thunderbolt
Thunder

Moltres lv. 65
Fire Spin
Fly
Flamethrower
Fire Blast

Arbok lv. 6? (ex. 62)
Acid
Stock pile
Swallow
Spit up

Marowak lv. 6? (ex. 64)
Bonemerang
False Swipe
Rage
Dig

I don't know if this is the greatest team levels and attacks or not, but can some one tell me by rating this answer? I hope I helped you! Good Luck in beating the Elite Four!!!

Charizard Is The Only One Which Is A Good Level, Mine Were All 65+ When I FIRST Beat The League, 2nd Time They Are All Stronger, Alot Stronger

Your guys are a little low on levels, maybe all up to 60. And how in blazes does Charizard learn blastburn!!!!!!

Your problem is you're weak levels. Your Charizard, while at a good level, is weak againt Loreli, and not affective against anything you're going to face.

Train up your Zapdos into the sixties or seventies, and get rid of detect and either Fly or drill peck. Teach it Thunder cause your going to need a damn powerful electric move against Gary's Blastoise and Loreli's gang of water losers.

Keep one of your flying moves unless you intend to use Moltres as your flying type Pokemon to kick Bruno's bum. Train up your Articuno and teach it a good ice move which is acurate and effective. Ice beam would suffice. You've two fire Pokemon, which isn't going to help you beat the Pokemon league.

Try to involve some different types, such as a psychic to kill Bruno instead of another fire Pokemon like Moltres. The psychic Pokemon can also beat up Agatha's team of ghosts. Basically:

For Loreli, have a Zapdos between level 65-75 which knows these moves: thunder wave and thunder. Drill peck or Fly if you won't use psychic pokemon. Crush Loreli and move on.

For Bruno, a psychic or flying Pokemon will lay it to him heavy, and I shouldn't need to mention what moves you need if you're either.
For Agatha, a psychic or dark Pokemon will beat her to the ground, although a psychic Pokemon will kill her arbok much faster, because unlike dark it is super effective.

For Lance, stomp your authority onto him with an ice pokemon. That ought to kill him.

As for Gary, you'll need Zapdos to kill both his Pidgeot and Blastoise and Gyrados. Despite that, you'll need a variety of other types too.