Flywheel Weight for a '05 YZ450F

1 reply to this topic
  • trubes

Posted January 12, 2008 - 08:15 AM


Has anyone added a Steahly flywheel weight to their 05 450? They show 4 different weights. 16,13,10, & 7oz. I am thinking about getting the 10oz. Let me know what your experiences are. I race in the expert class in District 37 and MRAN desert series. Thanks

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  • grayracer513

Posted January 12, 2008 - 09:05 AM


I haven't used bolt-on weights because I believe the welded ring weighted flywheels are a better approach. For one, you never have to concern yourself with them coming loose, and they are balanced when they are modified. For another, the welded types add more inertia mass per ounce of added weight because all of the added weight is out at the edge of the flywheel. Some of the mass of a bolt-on is in the central mounting flange, where it adds very little inertia.

I had a DRD 8 oz ounce on my '03 (their largest weight), and I said many times that the bike should have been built with that flywheel. It would have been about equal to a 10-12 ounce bolt-on weight, for comparison. The effect on the engine's ability to accelerate was unnoticeable; the engine felt just as snappy and responsive as before, and the bike was not one bit slower. What was noticeable was that it had much less tendency to rip the rear tire out of the ground as soon as I touched the throttle, and I could find traction on loose ground under acceleration much more easily, and with far less conscious concern over managing the throttle.

I'm currently running a GYT-R 9 ounce off-road flywheel on my '06, and the biggest difference I notice on that bike is that when I'm picking through tight spots at the bottom of a ravine, the engine pulls much more smoothly at low speeds under a load, without so much of the harsh thrashing and slapping against its own compression as with the stocker. Much more like an old school thumper.

There is no loss of acceleration or power in either case. The effect is somewhat like raising the gearing a notch or two, but without changing the rpm/speed relationship.

I won't knock Steahly weights. They are a good product used by many people very successfully. I just made a different choice, that's all.

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