How to Build a Yamaha YZ125 Engine | 1994 - 2001 Full Build Step by Step

[@MichaelSabo]

Hey guys, Merry Christmas! This is the 1998 YZ125 engine I got in bins (literally.) I decided to restore it and turn it into a mild 144 big bore and it became the heart of the Grape Ape build! What bike should I build next? For people using this as a tutorial, all chapters and tools are listed in the description 🤘

[@pnwmotoshorts7430]

Would love to see a trx90 build!!

[@muddymir3796]

I think a lt250r would be cool, you have already done a trx250r and building the lt would be cool.

[@DowneastTackle]

Love all the Videos Mike great work.. next projects you should consider, CR 500 Trike (Stroker) or a Polaris Scrambler 400 2 stroke

[@seantheperson923]

ltz400

[@losi8ightyew]

Since you dont do streetbike stuff. A kx500 would be nice!

[@kurky72]

The detailed on the build is just beyond perfect, luv these videos.

[@MichaelSabo]

I appreciate that Kurt, glad you enjoy the detail!

[@scrappyhustler7467]

I don't know if I've ever heard a cleaner crispier and snappier 125 rebuild like this unbelievable job mike!

[@westcoastsoul5421]

It’s like watching Bob Ross painting like I can watch it forever. Keep up the perfection of your detailed work. Videos well thought out as well.

[@MichaelSabo]

Haha, I'm gonna have to grow an afro; thank you for the love man! Merry Christmas!

[@davidberlingeri9783]

Thank you for not "time elapsing" your videos. Your details and explanations go a long way when your learning new things. By far, the best 2 stroke engine rebuild video for the DYI guys and gals👌

[@oasis618]

I love these videos, they give me the false hope that even if I had all of the special tools I could pull this off without installing something backwards like making the piston point down. Great video though!

[@Davido50]

You can do it. Get a great manual like Clymers. Go step by step! Double check yourself. Mainly u need some good basic tools & a TORQUE WRENCH 🔧. Learn how to use one! Use Maxima oils /chemicals or Yamalube ONLY.

[@MichaelSabo]

Hey Troy, I'm glad you like my videos; Like David said, you can do it yourself too! There's no better way to learn that to get your hands on an engine and learn from experience. You can grab a lawn mower or weed wacker from the trash and pull it apart then throw it away if you mess it up. Yes... I used to do stuff like that as a kid 😂

[@16Rippa]

I know exactly what that feels like

[@robertponsford8493]

You could do it dude I rebuilt a Suzuki rgv 250 v twin two stroke when I was 17 with no internet etc as I’m now 47 👍🏻

[@annoyerboka]

Keep good work.. Learn from mistake will make thing better.. We cheer for you..

[@TravisJones1979]

Wow wow wow wow best video yet.. EVER.. JUST WHEN I NEEDED IT THANKS MIKE your the best. We appreciate you!! Thanks for all u do.. dont for get to do your intros from time to time.. your very creative and we love it!!!!!!!

[@MichaelSabo]

Thank you Travis! I will work on doing skits in the beginning of my videos 🤘 Merry Christmas!

[@TravisJones1979]

@@MichaelSabo thanks Michael.. your the best!!

[@asherkrimmel5753]

Perfect timing cus I just got a yz to rebuild😂

[@MichaelSabo]

I hope this video can help; good luck with your build!

[@stephencrisson3595]

Me to i just picked one up I need to do a topend to on it cant wait to get it going

[@jollyshrimpo]

Got a 96 as a cheap project this video and all the linked parts are going to help big time thanks man

[@foobarmaximus3506]

Same trick for the Main Bearings. Heat the case, freeze the bearings - they will drop right into place. You can hear the metal "creak" as it tightens up on the bearing. Nice!

[@charlesgraham9954]

man i love the sound and smell of a two stroke.. thank u for ur time making this video.

[@MichaelSabo]

Thank you for watching it Charles 🤘

[@derekmullane231]

Awesome video Mike! I am a huge fan of these very in depth engine build videos; I just built a YZ engine (for my first time ever) about 1 year ago and this video would have been extremely helpful to watch beforehand. Also very good for a novice to learn about how the engine works without taking one apart themselves. Rock on!!!

[@forresttaylor6849]

Finally picked up an 01 yz125! My first yz. So now I’m watching when I’m actually going to do some work.

[@abbybonilla4511]

Saint Michael blesses us with another engine how-to on Christmas Eve! GOD YES!

[@MichaelSabo]

Hahaha, thank you Eddie; merry Christmas!

[@muddymir3796]

Thank you for finding ways to still upload great quality videos even with your shoulder!!

[@MichaelSabo]

Thank you for supporting and watching them!

[@lyndonjaynes8412]

These videos are really helpful, I bought a 1997 yz125 and I’m 16 and have no clue how to do this stuff, so thanks

[@Tbands707]

The bike sounds so crispy no lags nice pops when at idle no vibration just solid 👍🔥

[@caleblewman7496]

Shoutout to Michael sabo I followed your video step by step and completed my first 01 yz125 bottom end thanks so much man by far the most in depth and descriptive video out there keep it up man👌👍

[@anthonyschutz7201]

Yeeeesss. Just got a 97 yz125 with a disassembled engine. This is so helpful.

[@clifford4132]

This is my dream job to be paid to build and maintain dirt bikes and four wheelers !!! Love the channel

[@joshuasalisbury789]

Cheers for this vid I just bought an 2000 yz125 engine to put in my ybr125 road bike(originally 4 stroke) as a little project

[@njmxjunkie3128]

Mike man, I watched this when it came out but it came on again through auto play and I left it. Your build videos have come so effin far man! It’s so easy, straight forward yet detailed as hell.

[@lect0n7]

My 1998 YZ125 has a flywheel from a 1982 Yamaha YZ60 in it - the lower internal rotating mass & turning weight gives it torque like a YZ250

[@jeff6732]

You might not have ever went to school for this but you should definitely be teaching it!!!

[@MichaelSabo]

I appreciate that Jeff, thank you; hopefully these videos can help others out when they're doing their builds/maintenance 🤘

[@dannysheppard2882]

Great job mike, absolutely love your videos, I’m binge watching all your videos through Christmas break !! Great job young man.and merry Christmas mike .

[@MichaelSabo]

Danny, thank you so much for the compliments and for binge watching my videos; that helps me more than you know; merry Christmas!

[@cruddyjayvlogs7911]

All I can say is damnnn. You just inspired me to rebuild 5 engines how easy you made it look..GREAT job and work man

[@noahwiggins8746]

These will be my famous words I stg if “Michael built one I will” 🤤 you always show me something brother thanks for the tips love your porting and polishing surfacing is always a good practice

[@MrPopoffsun]

This guy is great, the best vids on youtube

[@0-01]

I just want to say that this work is great🔥🔥

[@MichaelSabo]

I appreciate that; thank you!

[@jonathanhammond9511]

The very best assembling video I've seen... Very good video footage and up close hands on info

[@dirtinburton3301]

Been waiting for this all day, As always man great work, Love the vids and Merry Christmas

[@MichaelSabo]

Thank you for waiting for my video; I'm glad you enjoyed it; merry Christmas!

[@Adamdub612]

junior builder? yeah right... your more on moderate to pro and i watch everything u put out and your buildz are always A1. keep up the good work Michael

[@JohnsonPortWorx]

If this video gets over 80k MIKE IS OFFICIAL. The grape ape video caught me by surprise. How does it beat out the banshee 😂

[@MichaelSabo]

I was surprised by the Grape Ape too man. The engine tutorial videos don't usually get big views off the batt but that would be legit if this video turns the tide!

[@jimmy1life]

Dude today it better

[@villesoinine9634]

@@MichaelSabo i love these and to see what is different from my way to yours

[@dieselmech7227]

Best video yet of a full rebuild assembly! Even provides time stamps and tool links! Awesome 😎 job ✌️

[@dieselmech7227]

Best video yet on a full rebuild assembly! Time stamps and tool links! Awesome 😎 job ✌️

[@kx85tate]

I ended up putting small washers that were the same size as the power valve shaft to hold my springs in place on my stock bore Athena kit for my yz125. Works as it should. Really wish I didn’t have to do that though since you pay a premium price for that kit. That’s honestly my only complaint about it though. Other than that it runs like a champ.

[@MichaelSabo]

I think I see what you're saying with the washers. I agree, it's a shame because it's such a small inexpensive (I would think) for them to upgrade and make right.

[@keithpeterson3447]

Put the crank in the right side crankcase first & pull it tight. The gear/spacer will want to pull the crank that way. Lay the right case on a flat surface facing up & drop in the transmission. Drop the left side case down on it & pull until the surfaces touch with a very minor squeeze. Drop in the case bolts & tighten it up. This should be super free spinning bottom with everything "set" as far as bearings on the crank. Never hit the crank. The idea of "setting" the bearings would be best done with a thick brass punch & a steel hammer. Then hit the cases near the main bearing bosses with the hammer & punch. The high pitch "ring" or "shockwave" will let any races that are "bound" to "jump" into place. I use the hot cold thi g but that process is hit & miss for people until they know how to do it consistently successful. Learning how to heat a bearing in the case without burning (overheating) the bearings or seals ect. The other thing that is a huge "no non" is the impact on the shift drum bolt. You HAVE to use a hand tool for that & make sure to rotate the drum to the "stops" before tightening. If the power tool hammer on it & the gears don't happen to want to let the drum "freely" roll to the stops, one of the forks can get bent as the drum puts a sideload on the fork & the gear is bound. Yamabond 4 is the absolute best for the cases. Thers vintage sleds tgat are 40+ years old & have never had the cases opened & they still run like new. The stuff never broke down even after 40+ years. 👍 Don't "knife edge" anything in the intake or transfer area. A rounded "bull nose" edge is best for anything facing the airflow. You can "knife edge" any bridge in the exhaust if you want. I still go with a "slight bull nose" in the exhaust because there is movement both ways in exhaust port & the first part of the pipe. Anyway, not meant to offend. All things that a guy like you can see would be of benefit. Rad bike. I have a 2001 sitting that I had been thinking of pulling out & doing a build. I can do a pretty rad build for a lot less than buying a new bike. Seeing your vid has me motivated to start pulling ot out for a winter project (I live in Wisconsin).

[@MrRippinonyou]

125 screamer they are a really cool mid sized rig to braaap around on . Another great build my dude its sick !

[@tonyppe]

Revs so quick and free, good work

[@jimmy1life]

A video on major differences throughout the years say look at this engine then a newer 2022 model what kinda things change because if that bike from the nintys is badass. I need get out and start looking for one.

[@MichaelSabo]

That would definitely be an interesting video to see

[@lulamorton5953]

Beautiful engine. You did an amazing job

[@MichaelSabo]

Thank you Lula!

[@forresttaylor6849]

Damn!! Check that out! That’s a trophy in itself! Sounds good too!

[@soulgivesoul07]

Thanks so much for making this video, I want to rebuild my YZ motor and this gives me some confidence. Very much appreciated

[@rcuniversespeed9447]

Love your videos Micheal…. I put them up on the big smart TV and watch them with the kids. The engine building ones are awesome instruction

[@Davido50]

I love Yamalube oils /chemicals but gotta say guys that *Maxima is truly top notch ..best of best lubes/oils/filters etc* . Most the pros run Maxima engine oils & 2 stroke oil. FYI. Great job as always Mike! Maxima looks awesome bro.👌 Merry Christmas!!

[@MichaelSabo]

Merry Christmas Dave! I agree with you; Maxima is a top tier chemical/oil company.

[@gregmorgan8103]

Awesome informative video bro! As always your a perfectionist thats why I like your videos you don't cut corners!!! Hope you heal up fast and dive into more builds. Merry Christmas🌲!

[@MichaelSabo]

Thank you Greg! Merry Christmas to you as well!

[@joaoraposo9519]

You know way more then many engeneers i work with...

[@alleybuilds5370]

i cant believe you don't have more subs.... just your video editing deserves more

[@waynesworld8930]

your liven my dream , thanks for all the tec support you deserve to be here an be a huge ch,Keep up the good work

[@Newmanrides]

Great advice and tips and tricks thanks ❤

[@tyor99]

merry cristmas very nice video. i once had a problem with one of those metal base gaskets that leaked coolant. now i slightly coat the gasket with rtv silicon. one tip with athena pistons is to chamfer the sharp edge on the bottom of skirt slightly this helps with the oilfilm on the cylinder. best wishes from austria.

[@MichaelSabo]

Merry Christmas from the US! Good tip on the piston; I will remember that the next time around!

[@seandaugherty2033]

Bro I love dirt bikes

[@ajp4101]

Awesome video. I learned a little and enjoyed watching. Keep up the good work. 🥳

[@trainwreck9549]

You deserve more views and interaction on these videos! Keep it up these are awesome!

[@theexisting1514]

thing is so clean

[@MichaelSabo]

Thank you man!

[@motododo4626]

Awesome video man. I hear you man no one likes looking at case half gasket boogers lol but I leave mine just because they say wiping it off can pull the gasket maker out and leave a spot for a leak. Thanks for for video man lobe this channel.

[@MichaelSabo]

Glad you like the video man! I don't know that I've had the gasket maker come out from wiping it but I could see it happening if its partially cured and has enough body to pull some out of the seam.

[@motododo4626]

@@MichaelSabo yup I've never had it happen either just makes my ass pucker thinking about draining all my oil at dunes hahahaha. But keep it up dude you are my #1 youtube channel I watch. Your content is sick and the rigs you build are amazing.

[@Davidsmithisyourdad]

That sounds crisp

[@BluesmaN420]

Thank !! My Brother.

[@denniswilder3014]

I use antiseize or grease under the heads of the bolts.so when you tighten up the bolts it doesn't bind up and you also get a better feel for the tourque.youd be surprised how many ft pounds is off just by binding

[@Fukinglexa]

Классное видео, все подробно показал и объяснил! Привет из России

[@NephewJamie]

Hope you had a great Christmas! thanks for teaching once again!

[@juliuscalmarez6599]

My dtg was buy last 1983 until this monster is alive

[@billyclevenger2632]

Hey mike great Job on videos. Finally after 30+ years. Someone who tells the truth about the steps they use to build. Even the little common sense things that would have instruction police loosing their minds. Because just sometimes that $800 pencil sharpener just isn’t necessary. Lol. Great work. Oh and yes normally they always start torquing from inside working opposing sides working your way out especially with gaskets. So that the pressure works the gasket out pushing any buckles out to the edges. You were already on the right track though. Love my Yamaha. You are smart enough that you should do a 660 raptor speedwino fuel injection conversion. Or maybe a micro squirt? People have changed a lot of machines. But I can’t find a single 660 raptor anywhere. I think everyone is intimidated by the twin carbs. But I have a feeling you could figure it out. I have about 3 fb groups that have all had questions about aftermarket fi. On our machine’s. I’ve been doing research. But quickly found myself financially not able to experiment. Just a thought. Thank you

[@edipray5638]

Sangat lengkap.saya suka sekali...keren mesin...buat mengerti dalamaan mesin motor...

[@MichaelSabo]

Saya senang Anda suka melihat motor dibuat! Terima kasih telah menonton!

[@edipray5638]

@@MichaelSabo selalu mengikuti video2 anda ..moga makin sukses chanelnya

[@rippinrheaume242]

Hi dont know if anyone caught it but before installing the crank gear on the clutch side you have to screw in the crank seal retainer he left it off in the video and I saw there was a missing screw hole and I had an extra retainer left over so make sure yall put that on before you bolt your clutch pack on, waste your time and have to take it all off and redo it again just to screw on the seal retainer

[@thomassylvestro9041]

Excellent video... Thank you

[@hannesdobbelaere]

this bike runs sooo smooth that i want to buy one myself! :-D, i ride a 2020 yz250f right now but always wanted to ride a 125/140 (150) to feel what it's like. i'd probably be slower then on the 250f but maybe more fun? definately something to try out! great video, i'll be consulting this one if i ever rebuild a yz125! thanks! cheers from Belgium :-)

[@Skip_98]

Hard work pays off! 💪

[@foobarmaximus3506]

Heat and Cold, folks. Heat and Cold. ALWAYS better than mechanical stress.

[@jridenour31]

This is a great video. I would have used a torque wrench on everything but that's just because I have a tendency to overtighten everything without one lol. Subbed.

[@sambuvca22]

nice job man! im currently rebuilding my 98 yz 250. very similar low end. THANKS!

[@danieljamespt]

LOVE your videos! 😎🤙 also you sound like Jeffery Dahmer

[@darrellfolk5284]

Thumbs Up of Course Bro! Merry Christmas Eve Again!!! 🤣

[@MichaelSabo]

Merry Christmas Darrel, thank you for the thumbs up!

[@johnkaze7437]

Great job 👍

[@thatonescrambler]

My 2001 needs a rebuild whoopee

[@keithparady2594]

Damn nice bike and good work man

[@MichaelSabo]

Thank you Keith! Merry Christmas!

[@nelsonkarrer6961]

Nice job Michael

[@MichaelSabo]

Thank you Nelson!

[@HELLTRACK1986]

Awesome video. Very thorough. Very helpful. 👍

[@robertponsford8493]

Great work man I watched one earlier of a guy rebuilding a little 2 stroke scooter engine and it was mistake after mistake I felt sorry for the guy as he was talking like he was an expert lol 😂

[@smward1126]

You should build more dirtbikes!

[@border411]

Thumbs up for using Kirkland Microfibers....

[@anthonycantando7255]

Mike as an owner of an fl350 it would definitely be sick to see you do a build on one!

[@corysexton3970]

I like the ending as well as the beginning because you have an interesting video but at the ending you make us stay by roping Us in on something LOL

[@dennisbrooks186]

Killed it as always bro!!!! I ordered one of them crank puller/splitter tools. And mine didn't come with the 2 steel bars. Weird. But yeah man I rewatch all ur motor vids all the time. I feel like I learn more that way. I never knew about the tight crank fix til now. Hope ur healing good brotha. Merry Xmas and thanks for the vid!!!

[@MichaelSabo]

Thanks Den, shoulder is coming along pretty good! If you ordered a Tusk installer, I'd contact rocky mountain because I'm almost certain it's supposed to come with the bars; mine did; of course that was 3-4 years ago, but I doubt they'd stop including them. Merry Christmas!

[@dennisbrooks186]

@@MichaelSabo I don't think it was tusk. I forget. I ca t find replacement bars anywhere though. Ill try them tho see if they'll sell just bars. Or make some from angle iron lol r.m. is sick tho. Ordered a ton of stuff for Xmas. It all came in time haha keep up the good work and heal up bro. Can't wait for more anything, but esp banshee stuff

[@homestedfrustraions2042]

Guy, you are ment to do this. Great video. So much great content. 👍

[@xSN1P3ZZzz]

i have the mind of a child. i lost it when you said “this goes right in ur shaft right here”😂

[@connersnow298]

Awesome vid and edits and filming and toys and shop and knowledge

[@ahsokatano6059]

nice build, bike looks wicked

[@mikeyacullo]

Deffinitly neeed the right tools

[@DowneastTackle]

Merry Christmas To you and your Family Mike, I see that you have used The assembly lube on the bearings, If you want to Prolong them Use Royal Purple Oil Synthetic, it will penetrate the steal and Keep the Bearings newer longer...

[@MichaelSabo]

Merry Christmas brother! I wonder if royal purple makes an assembly lube? I'd definitely be interested to try it out; thank you for the tip!

[@nathanmiller9545]

Love your videos mate you make it look easy but I know it’s not, good job

[@davidstoner27]

Job video bro have a good xmas glad to see your arm is not stuck on your chest lol one day at a time

[@MichaelSabo]

Thank you Dave! Merry Christmas bro!

[@chud2070]

What’s the reasoning for advancing the timing? Fun video to watch!

[@remymorgan5931]

You never put the video link in about the squish but great build yew 🤙

[@mikeyacullo]

I could totally build one if these now. I just Gotta get some new tools

[@alerusso5356]

Amazing video 🤩💙

[@robertponsford8493]

The smallest gear on the primary shaft that meets the largest gear on the secondary shaft will be 1st gear and vis versa for top gear

[@royalracingtechroyalracing6128]

Sabo built 🛠🎄🙏

[@JohnWick-hx7bc]

“Really nice they come separated” mixes all the bolts

[@dimmacommunication]

The thing I don't like about big bores is that they don't have 3-4 sizes of spare pistons like the 125s do.