UPDATE:
Clutch of Ji-Kun dropped on the 199th attempt!!!
_https://i.imgur.com/vgnfQDN.jpg
I’m coming up on the 200 mark on kills of Ji-Kun.
I’ve been running Throne of Thunder on 15 different characters.
I’ve always run Normal/Heroic 25-man.
I’ve gotten 7 Ji-Kun Hatchlings and 0 Clutch of Ji-Kun.
Is this just REALLY bad luck?
Oh, sweet summer child. You’re new to the mount farming business, aren’t you?
_https://simplearmory.com/#/us/dalaran/sabryx/collectable/mounts
No… no, I’m not.
Then you should be well aware 200 kills is practically nothing.
You’ve used up all of your good luck getting the Astral Cloud Serpent is why. 
lol.
On a side note, I got extremely lucky with Reins of the Thundering Onyx Cloud Serpent. I got it on the first kill.
/cry
(10 chars)
Keep in mind that it is theoretically possible to never get it even if you ran it 10 million times. Though I think your odds at that point would be like 99.9%. It really is just a numbers game.
I got the Astral Cloud Serpent, Thundering Cobalt Cloud Serpent, Spawn of Horridon, Clutch of Ji-Kun, and Rivendare’s Deathcharger all in the week before classic started.
Today I got the Big Love Rocket.
Wow. That’s quite lucky. I have simply come to believe that I can use up my luck, but for some people, like my friend who keeps teasing me about their Astral Cloud Serpent dropping for them again during a gold run, they don’t know how to stop being lucky like dang it man! 
I figured my luck was used up and played classic for a while.
Yes, friend quit for 5 months came back we went and did jikun and it dropped, very bitter.
A lot of people misunderstand probability, and “luck” is made up nonsense that simply doesn’t exist. It’s one of those things we humans created not only to cope with probability, but also to assign “control” of rare occurrences to some ethereal undefinable power.
Collectively, we have a bad habit of doing that. 
Mounts that have a 1% chance to drop have a 1 in 100 chance of dropping each time. This chance does not increase or change with each kill. Your chance is 1 in 100 after one kill, five kills, ten kills, a thousand kills, a million kills, etc.
“I’ve logged X number of kills, shouldn’t I have this already?” isn’t really a thing. People assuage their pain by coming up with more probability to define your chances after a certain number of kills, but that’s pure semantics.
It’s 1 in 100, every time, full stop.
You’ve rolled a 100-sided die 200 times and never hit the number you want to hit. You may roll that dice once more; you may roll it another thousand times.
My worst mount farm to this day remains the 1% Blue Proto Drake drop from Skadi. I logged somewhere in the neighborhood of 330 kills before it dropped for me.
Keep rollin’.
I’m up to 481 big love rocket kills this event, does it still drop? 
I’ve heard legends and fables claiming it does. LOL.
For most rare mounts, I believe it’s a 1 in 100 chance to drop per kill.
Whether you killed it 1x, 200x, or 2000x, your chance is always the same.
Statistics states the more you kill the boss, the higher your chance will be. This is because of the sheer number of attempts, not because the mount is more likely to drop.
Keep farming my friend.
Everyone hates people like you. 
I don’t try for a lot of mounts but lucky people make me cry over my 1200+ attempts at the love rocket. 
I swear the mounts only drop after you vocaly announce that you are quitting. I quit running mounts for like 2 months then i came back to farm some legendary otems like valan’yr from ulduar, and all of a sudden I get mimirons head 2 nights ago. So maybe tell vlizzard you are quitting, and they will flip the magic switch to give you a mount to make you stay? Lol
Be gentle…
Better this poor person’s dreams are shattered now than later.