Hi all Master Yi players and Moba Fire readers!
This is my first build posted on web so I hope it will help someone. It's Master AD carry build, taht is not the typical with some Phantom dancers an Bloodthirsters. It's Pentakill build.

So we start with Dorans blade, but if you want, start with Boots of speed and potions, but why is Dorans blade better? If you have Masteries and Rune page as I have, picking first spell Wuju style and first item Dorans blade can give you more than 100 damage easily. And for first blood you will need it, after using Wuju style active, you gain additional 15 damage and you slay champion, because they got about 500 HP at start.

Second full item is Tiamat. Tiamat is one of the most OP items for Master yi. As one of melee AD carry you get the passive of Tiamat with 50 % damage to all nearby enemies, you will wonder how fast you get creeps.

Berserker's Graves - standard AD carry boots, for Master more crucial as for others. Because you will mostly kill with basic attacks, you need great attack speed.

Next another Tiamat. OMG why two Tiamats?? Because the passive from Tiamat is not unique, so it's effect stacks. So now you deal 100 % of your damage to all nearby enemy units and no wonder how fast you get creeps and more - doublekills. Just jump at enemy with Alpha strike and finish them with basic attack! It's easy, trust me.

The last two items are standard ones, to rise your damage, critical strike chance, movement and attack speed. If you want and have enough money, sell Dorans blade and buy Infinity edge.

OK so how to get Pentakill with this build? To start think about Pentakills. When you ca have one?

You can have Pentakill when all the enemies are close each other.
Enemies are close each other, when trying tactic called "All together"

So late game, when enemy team goes "All together", come there and have Pwnta. You can't have Penta alone, you need your team, but when you have at least 3 teammates near, jump into the weakest enemy with Alpha strike and kill him with basic attacks. Then go to second weakest etc. With two Tiamats you will kill them as you would killing minions. But don't forget this: You can't do it yourself, you need your team to help you.