I know this build looks stupid, but trust me, its completely viable. Yi's style of play complements this style of build, especially in the late game. In teamfights, if you get onto the ADC, they'll be dead in seconds, giving you a nice reset on abilities.

Pros:

High burst
Good farmer
Great teamfight contributions

Cons:

Very squishy
Can get bullied put of lane against a high burst toplaner

This phase is the most difficult stage for this Master Yi build. Master Yi is a fantastic farmer, especially with a statikk shiv, but is very squishy, even if you have meditate up. I usually stay defensive and just farm with my q, trying hard not to spam it though, as going OOM can be a huge problem for laning stage Yi. Once you get a statikk shiv, things get easier. This is when you can start to bully the opposing top laner, as now you have a decent crit chance, and a good attack speed and nice movespeed if you need to run away. Don't be hesitant to use your ult to escape from a gank. It has a very low cooldown anyway and dying allows the other laner to get a strong advantage.

In teamfights, Yi's main goal is to go onto an enemy ADC or APC, and burst them down quickly. when you get an Infinity Edge, this is very easy to do, as your q can serve as a dash to an engage. After both carries are eliminated, go onto the top laner, even if they are tanky,. they still do a lot of damage, and eliminating him/her will make the teamfight an easy win. when going in, be sure to use your ult, as the refresh on your abilities allows you to keep you high damage up throughout the whole teamfight

I hop[e this build guide has been good help to anyone who tries this out. Feel free to message me any comments or improvements on this build. If you like this build, be sure to rate it well, or not if you don't like it