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

Yamaha YZ125 1994 - 2001 | Complete Engine Build Step by Step
#2stroke #yz125 #yamaha

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?

CHAPTERS

0:00 – Intro

CENTER CASES

2:08 – Crank Installation
5:00 – Transmission Installation
5:45 – Shift Forks and Shift Drum
7:09 – Assembling Case Halves

STATOR SIDE

12:29 – Stator Installation/ Timing Adjustment
13:24 – Flywheel Installation
14:50 – Stator Cover Installation
15:40 – Sprocket Assembly Installation
16:35 – Case Saver Installation

CLUTCH SIDE

16:55 – External Shift Mechanism Assembly
19:16 – Shift Shaft Installation
19:50 – Kickstarter Assembly
21:32 – Kickstarter Shaft Installation
22:35 – Idler Gear Installation
23:45 – Primary Drive Gear Installation
24:53 – Clutch Assembly Installation
26:35 – Tightening Primary Drive Gear
27:07 – Clutch Pack Installation
28:48 – Pressure Plate and Springs
29:52 – Exhaust Governor and Actuation Arm
30:50 – Water Pump Gear Installation
31:15 – Right Crankcase Cover Installation
32:06 – Clutch Cover Installation
33:37 – Water Pump Impeller
33:56 – Water Pump Cover Installation

TOP END

34:19 – Ring Installation
35:27 – Piston Installation
37:04 – Athena Cylinder Explained
39:13 – Power Valve Installation
42:59 – Athena Base Gaskets Explained
43:49 – Cylinder Installation
45:30 – Power Valve Arm Assembly
46:00 – Power Valve Covers Installation
47:25 – Cylinder Head Installation
48:45 – Reed Installation

SHOWCASE/CLOSING

49:10 – Showcasing the Engine
49:54 – Running/Revving the Engine
51:13 - Closing

PARTS AND TOOLS IN THIS VIDEO - (These links may be affiliate links that I get a kick back for; there is no added cost to you)

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[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 🤘

[kurky]

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

[scrappyhustler]

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

[westcoastsoul]

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.

[TravisJones]

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

[oasis]

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!

[asherkrimmel]

Perfect timing cus I just got a yz to rebuild😂

[davidberlingeri]

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👌

[jollyshrimpo]

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

[charlesgraham]

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

[foobarmaximus]

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!

[derekmullane]

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!!!

[muddymir]

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

[lyndonjaynes]

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

[forresttaylor]

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

[caleblewman]

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👌👍

[abbybonilla]

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

[Tbands]

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

[njmxjunkie]

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.

[noahwiggins]

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