Master Yi is among the most highly played champions in the League. He is known for his ability to traverse the map, take down key targets, and run away faster than Ashe's ult. Viable as both AD or AP, he is also quite versatile on the battlefield. Though many champions can do these things, and a few can do better, no one can beat Yi at The Backdoor. Master Yi is a formidable opponent in any lane, but nothing is more frightening then an enemy Yi pushing towers faster than an entire 5-man team.

This build solely focuses on Yi's tower-pushing ability. Any free moment is spent in top or bottom lane, destroying towers and pushing the minion wave forward. As Yi, your abilities center around damage output, and you will compliment this with your items, runes, and masteries. When playing Master Yi this way, you will find yourself single-handedly winning games for your team. While following this build, you must remember the objective of the game: to destroy the Nexus. Anything else is just a side-quest to get you there, INCLUDING getting kills and farming.
Prepare your anuses, and let the backdoor action begin.

Generic AD-heavy runes, with armor penetration marks and quintessences ( Greater Mark of Desolation, Greater Quintessence of Desolation), flat armor seals ( Greater Seal of Armor) and magic resist per level glyphs ( Greater Glyph of Scaling Magic Resist).
This will increase your damage output, as well as give you some defense during fights.

Alternatively, get movement speed quintessences ( Greater Quintessence of Movement Speed).

AD-heavy masteries. Take Summoner's Wrath for its increase in Ghost's speed boost. Alternatively, you could invest in Butcher and Demolitionist , but you'll be doing far too much damage for it to be noticeable.

Why this ability sequence?

As your typical AD Yi, your primary skills should be Wuju Style and Highlander. Generally speaking, you want to have both these turned on fighting enemies, or, in our case, pushing towers. Next, Alpha Strike is used for quickly dispatching minion waves, though it becomes less effective as you near your full build(it becomes faster to simply hack away with basic attacks). However, Alpha Strike is still very useful for catching up to enemies, or dealing that last bit of damage when they are out of your attack range. That leaves Meditate. With 0 AP to use, Meditate will only be healing about half health at Level 18. In fact, it is almost always faster to run away and heal through life steal. However, it can be a useful last resort in desperate situations.

Preferred

Ghost

Ghost allows you to speed away from the lane as soon as the enemy appears. It can be used as a boost to your ultimate Highlander to be able to outrun anything.

Teleport

Though Master Yi is undoubtedly fast, even without Ghost or Highlander, even he cannot be everywhere. Teleport allows you to get where you want, when you want. It allows you to out-level your opponent in the laning phase, and can often be a game-winning tool, especially with someone like Backdoor Yi.

Alternatives

Exhaust

Not as useful as ghost or Flash while chasing or running from an opponent, but can be helpful in those rare challenging one-on-one fights. However, rarely should you be trying to chase down an enemy. As Backdoor Yi, any spare moment should be spent pushing one of the three lanes.

Flash

Flash is generally a good spell to have on any champion. It is an excellent spell for champions with fewer escape tools (such as Yi), but is second to Ghost, as enemies can follow up on your flash with a skill, or their own flash.

Heal

Heal has been buffed quite a bit, and is often chosen by AD carrys. But you aren't a AD carry. This limits its use to surviving a chase. But you probably would have been better off simply avoiding it.

Revive

Like stated above, your primary objective is destroying towers, inhibitors, and winning the game, NOT getting kills. This makes revive slightly less useless for your sake. It gives you a slight speed boost upon use and, well, brings you back to life. More time alive = more towers pushed. Though unlikely, Yi might also be able to save his team during an enemy ace.

Ignite

Widely preferred for solotops and mids, ignite is clearly has its uses. HOWEVER, ignite can't help you push towers, and it can't help you get away. The most use it will do to you is pick off low-health champions you are too lazy to chase after. Nobody likes a lazy champion...

Surge

You are AD, not AP. The only thing you will gain from this is the bonus damage to Alpha Strike, and the 355 increased active speed. Honestly this just isn't worth it.

Clarity

What are you doing with such low mana anyways? Why are you burning so much mana? You're Yi not Ryze. But in those rare instances where you just don't have the 100 mana for Highlander to get away, and your Ghost is on cool down, clarity could be a life-saver. What are the chances of that though?

Smite

Get out of the jungle, you solotop!

Promote

Kill the minions yourself you lazy ***.

My Preferred Item Build

Alternative Item Builds

Maximum Damage Output

Movement Speed

Survivability

Attack Speed

Not recommended, but plausible