Hi Everyone This is HolyRider with a Master Yi Build/Guide!Before you start reading on,I just want to tell you that this is my first build.Don't exept a super awesome build.Second of All,This will NOT guarantee you that you'll be winning 24/7 every game.
PLEASE NOTE:This is only beta version.Not everything is completed here.

Pros:
Fast,at about 500 speed!
Easy to Play
Really High Damage(Wuju Style + B.F. Sword)
Really Easy to Escape
Backdoors well

Cons:
Squishy(Not When You Get Frozen Mallet)
Blindings are Master Yi's weakness(So basically when your agaisnt teemo your out of luck)
Someone Exhausting Master Yi would disable the damage effectiveness
Mana Problems when constantly spam your q

Flash-If you were slowed,you would use flash for escapeing.You would be asking right now"you have about 500 Speed,why would you get that?" Well,basically if alistar stuns you and head butt to the tower.Your dead.Flash is a very quicker escape.

Ingite-Great Use for 1v1.Use this when you were about to kill someonebody when she/he is about
30hp.

Exhaust-Please,you have 500 speed without Highlander.Is your opponent really that fast?

Teleport-Use this if you have lack of mobility.You can switch ingite over teleport if you want.

Ghost- This is your choice if you want to pick this or not.If your playing someone fast,most recommended choice is this one.

Smite-Sorry guys,you'll need another reliable source for master yi jungle.

Fortify-Leave your pure tank for this one.

Rally-!?Feel free to use this if you are trolling

Revive- Same with ralley.

Clairvoyance- Save this for your supports.

Heal-Leave this for supports.

Clarify-if your really haveing ALOT of mana problems pick this one.

Cleanse-Use this when the other team has alot of CC.

For Masteries,I would go 21/0/9