GYTR Flywheel Weight For YZ450FX

What it is

• 1.8 oz heavier than the stock flywheel.
• One-piece welded design.

The GYTR YZ450F/FX Weighted Flywheel is an OEM Yamaha replacement flywheel that’s 50g (1.8 oz) heavier than stock, increasing flywheel rotating inertia by 15%. Yamaha states it smooths low-to mid-RPM power delivery, enhances engine control and improves stalling resistance during low-RPM off-road riding. The one-piece welded weight retails for $254.99.

How it works

• Less jerky and responsive power delivery.
• Increased control and more appealing to a wide range of riders.
• Easy install that takes mere minutes.

The 2026 Yamaha YZ450FX is one of the most polarizing bikes among the DBT test riders. The younger, more aggressive riders praise it for its precise chassis and powerful engine while our more tenured (old) riders complain about its aggressive power delivery and rigid chassis. One of our ongoing projects is to see if we can make some minor changes to broaden the bikes appeal. 

The GYTR Weighted Flywheel sounds like a perfect addition for anyone wanting the calming effect some additional rotating mass will bring but we were a little skeptical. We’ve tried heavy flywheels on many bikes over the years and adding 50g is a pretty small addition compared to most. Personally, I wondered if I would even feel the difference. 

We installed the flywheel at the track so we could ride it back to back and the whole process only took a few minutes. It does require an internally threaded 24mm flywheel puller so be sure to source one if you’re thinking of this upgrade. After completing the install, I rode across the parking lot and to my surprise, I could already feel the difference. The YZ is very abrupt just off idle and riding at slow speeds can be a little jerky. Immediately I felt those throttle induced jolts smooth out. Once out on the track it did exactly what we hoped. The added weight smoothed out the power delivery and made it easier to ride, more controllable, and less prone to stalling. To be fair we’ve never had stalling issues on a track, but the YZ can stall fairly easily in tight conditions. What it didn’t do is change an aggressive race bike into a mellow trail bike. It’s still one of, if not the fastest 450 in the class and adding a little bit of flywheel weight isn’t going to change that, which is a good thing. It just made a noticeable change that will appeal to a lot of riders. I’d even go so far to say that this should be standard on the FX because it really does improve the bike, especially in off-road conditions. 

Our youngest and fastest testers don't hate the weight, but with our 14/52 gearing, they found it harder to pull third gear in corners as it takes longer to build RPMs and get into the meat of the power. However, they do appreciate the increased ridability and control of the 450FX engine without taking away its best traits.

Heavy Flywheels have their supporters and detractors and I’ve been on both sides depending on the bike. For the YZ450FX, I think there will be far more positive reviews as it just makes the bike better in most conditions for a lot of riders. It’s a subtle change, but it makes a noticeable difference. Unless you’re an elite level rider that spends most of their time in the sand, I bet you’ll feel the same. If you want to tame the beast just a bit, enjoy spending some time in tight technical terrain, or want to increase the comfort and control of the bike, this is an upgrade well worth the money.