On this week’s Two-Stroke Tuesday we take a closer look at the 2020 Yamaha YZ125X. The Dirt Bike crew is in South Carolina and will have a chance to ride this machine later in the week. Stay tuned for a video and action shots! We packed 2-Stroke Theater full of 125cc machines and if you are a fan of off-road two-strokes don’t miss the exclusive link to our 1996 KX250 project at the bottom of this post.

Although the 2020 Yamaha YZ125X is based off the MX model it does have a list of items that are different. The YZ125X is equipped with an 18″ rear wheel that has a 110/100-18 Dunlop AT81 tire. Yamaha says it went with a slightly larger rear tire for improved traction. The rear sprocket is also larger, YZ125X has a 50 tooth version where the MX model is a 48.

Just like the YZ250X the 2020 YZ125X has a kickstand that is designed to be tucked-in and out of the way but convenient to use when needed.

The YZ125X engine is almost identical to the MX model but does have different head specifications, power valve shape, ignition timing and jetting specifications . Instead of putting a larger tank with more fuel capacity Yamaha just added a fuel petcock that has a reserve feature. Below are a couple pictures that will explain the head and power valve changes. Yamaha’s goal is to increase bottom-end usable power.



Internal valving on the shock and fork has been changed significantly to work better in off-road type situations.

The YZ125X does not come equipped with hand guards(Not sure why) but these Cycra units are available through the GYTR accessories department.

Yamaha hopes that with very targeted changes to the YZ125MX platform they can capture the off-road enthusiast with the YZ125X. We haven’t had a chance to ride the “X” version yet but we like the fact that Yamaha is putting in the effort to make off-road specific models, Especially two-stroke off-road models.


If you like off-road 2-Strokes check out this 1994 KX250 build we did. Click the image below for more!

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