I Rebuilt My YZ125 In A Closet!?

It was more like a hallway, but the work area was still smaller than I wanted. I picked up a 2003 Yamaha YZ125 that had some major frame damage. The bike ran well but was not ride-able. The two options were to scrap the main and sub-frame, or take the time to bend and weld them back to their somewhat original form. Either way I would have to strip the entire bike down to the very last bolt and tie-strap. Just by looking at it I could tell this was going to be a difficult, yet exciting project.

I got to work tearing down everything on the YZ125, starting with taking the engine out of the frame. There were a lot of nuts and bolts from the plastics, engine, radiators, frame, and other miscellaneous parts that I had to organize into little zip-lock bags so I wouldn’t lose track of where they went when I put them back on the bike. In the middle of this process I got the sub-frame bent back and welded so that it would fit like normal. Being me, I decided to go the more challenging route of getting the main frame welded instead of paying a couple hundred for another one. Once I took everything off of the main frame my dad helped me by welding it.

I wanted to make this bike look good when it was finished, so I sanded and cleaned off the main frame to get it ready for painting. It took a while, but I managed to find some paint that was close to stock color shade. I then painted it with a few coats to make sure that it wouldn’t peel or chip right away.

Tear Down Process

Tear Down Process

The rebuilding process began just after the paint on the frame dried. This is the part where I had to move everything inside…. I started with the foot-pegs, front-end, rear shock, and swing-arm. Those went on pretty easily, so I then took the whole engine and bolted it up to the frame. The rear-wheel and handlebars with controls were next to go on. After that it was just the electronics, carburetor, plastics/tanks, seat, and a few miscellaneous things, such as the exhaust system.

Rebuild Process - Frame painted, front-end, rear shock, and swing-arm on

Rebuild Process - Frame painted, front-end, rear shock, and swing-arm on

Rebuild Process - Engine in, rear-wheel, handlebars on

Rebuild Process - Engine in, rear-wheel, handlebars, and controls starting to go on

After working inside for some time, this project was well worth the outcome. In the end I think the bike looks good, and I learned quite a bit more about rebuilding these modern dirt bikes (Check out my other article, “How I Built A YZ250F With A Box of Scraps” if you liked this one). Let me know what you think, and if you want to see more projects like this just give me a shout. Thanks!

-Tom Stark

Finished '03 YZ125 Project

Finished '03 YZ125 Project


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  • iksan says:

    thank you for picture

  • Mike b says:

    Hey which paint did you use to paint the frame? It looks really good. I’ve been looking for paint for my 00 yz125 forever. Can’t find anything even close to oem

  • Tom Stark says:

    Yeah, it took me a while to find something because I couldn’t find a can of oem paint in stock. I just bought a spray can from home depot. Don’t remember the color code, but it was something like deep blue metallic (I can check if you’d like). When side by side with the stock blue you can see the difference, but from a distance you can’t tell.

  • Mike b says:

    Yea would you mind finding out exactly what you used and was it a spray paint ? I’d really appreciate it, thanks!

  • Francis says:

    hey stark maybe we can be business partner I have a motorshop and maybe we can sell bikes here in Philippines.

  • mitch says:

    nice bike mate, looks like you spent alot of time doing it. im looking to buy a yz 125, just cant find the right one

  • […] Well, after weeks of picking at my wallet this bike has finally been put together and is running. It just needs a couple things put on to be ride able. So once I get those together I’ll take it out for a spin. The process was long and somewhat miserable, but I think I learned a lesson and gained more experience and knowledge about these modern four strokes that basically took over the world. In the spring, if not sooner, I will be putting on some new bling to make this baby look new, but as of right now it’s a clean bike that runs. Thanks for checking out this rebuild process, and make sure to check back in the near future for another bike rebuild! (If you liked this article make sure to check out my other rebuild, “I Rebuilt My YZ125 In A Closet!?” […]

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