YZ125 Engine Teardown (Race Motor Build Part 2)

In this video I tear down my 2018 Yamaha YZ125's motor to prepare it for a full rebuild. Enjoy!

[@gabewilliams5993]

Always a good day when AK moto uploads. You’re turning into the next Cameron Niemela.

[@donalddonaldson7211]

No, he’s the first AKmoto

[@groovytv3833]

This inspires me to get started on my kx

[@donalddonaldson7211]

Did u get started ? I’m still working lol

[@kylewebber8300]

Awesome video man. Thank you it was very helpful for me doing an engine tear down for the first time.

[@JAVTROOPER]

Crystal clear tutorial. Bravo AK 😘

[@DanMX2112]

Nice work dude, motor is gonna look great! Keep it up!

[@user-bl6to5eq8m]

Very Awesome man

[@donalddonaldson7211]

What a unit!

[@user-pg3ve3js8n]

Nice video 🤙🏽

[@kurtdavidson9808]

AK, always excited when you upload a video. Did you actually have an engine failure or did you just decide to do a rebuild? I have a 2021 yz 125 and I wanted to know at what point I should be thinking about a new top end. Because I am just learning about the mechanics of these machines I definitely don’t want to cause damage to my engine due to neglect. Scary thought. Thanks again for the great videos.

[@azkrie5246]

I’ve head people consistently getting 60-70 hours out of a top end with the OEM piston

[@sethmacgillivary1281]

Did it blow up? How did you know it was bad before it was apart?

[@shonrob1620]

Can always leave the kick starter gear in the case

[@DimitrisTsoykalas]

Hi,sorry if my subject is not directly relative to this video. I have a question. I have a 20 years motorbike (yamaha crypton) and because may i had for some period not checked oil or abused trasmission,,, anyway it started to do a clik-clik noise ONLY in 2nd gear. So my mecahnic here (in greece) says that its not a big thing and it is just that "hit the 2nd gear ... gear" And he inseast that we dont need to open-teardown the engine. I asked him..ok..but is it possible that this 2nd gear problem will may damage ALL other components some time in future? He says ..no..no problem...and that is just a little DISTORTION on the gear that wii not affect anything. --- Ok..here is my 2 simple questions that i hope to not take much of your time to answer. a)How is this damage called in english in order to search and learn more about it? b)Are you agree that i can leave it like this damaged (saving ~200 euros) and will not affect other components like "some teeth broke and broke all engine"? Thank you in advance and again sorry for my strange question...i just know to change my cluch disks ,brakes,oil etc

[@brettricker3322]

Quick question right after you take the transmission out do you use your case splitter to pull the crank out of the case?

[@donalddonaldson7211]

I thought you had to split the cases to access the transmission?

[@nelscot]

No push it out from the other side

[@sethmacgillivary1281]

How many hours did the crank last and how many do they normally last

[@kevinhauck4518]

Great video it’s very useful. One question though. What are the dimensions for your engine stand thing you made out of wood? I want to build the same thing.

[@anthonysansotta2200]

I just made one of these, did it 10x13 and it works perfect

[@alwaysstalking3002]

15:12 deez nuts

[@ccnb1247]

What's the shaft called that you took out of the transmission with the ball bearing

[@ccnb1247]

My bike did not have the rod in the transmission shaft you pulled out before you split the case

[@akmoto_]

The setup may vary from year to year, if you are unsure just lookup an OEM parts diagram from a website like Motosport or RMATVMC

[@julesm5574]

Hey AK moto, I need to make an oil change on my yz125 i wanted to ask what oil you recommend and how do you get your measurements?

[@donalddonaldson7211]

10-40 750 ml I think

[@donalddonaldson7211]

Correction I use 15-40 rotella due to how hot it gets here in TX