Rekluse/heavy FW question

6 replies to this topic
  • WB450

Posted March 18, 2010 - 07:08 AM


I'm installing a Rekluse Z-start pro on my 07 450 and I currently have the heavy GYTR flywheel, my question is should I go back to stock now that I have the Rekluse or stick with the heavy FW? With the Rekluse I shouldn't need the heavy FW right?

  • ForsheeMS

Posted March 18, 2010 - 08:30 AM


I would try it both way and see which you like better. The extra weight of the Rekluse could match the effect of the flywheel weight alone. It's really easy to swap out flywheels.

  • grayracer513

Posted March 18, 2010 - 09:23 AM


This question comes up all the time, and the thing you need to realize is that the flywheel and the Rekluse really do two different things.

Personally, I would install the GYT-R off-road flywheel on any '06+ YZ450 I owned, regardless, but I'd do it for the improvement in low speed operating characteristics, not to prevent stalling. There's no performance hit taken from running it, so why wouldn't you?

As far as the extra weight of the Rekluse adding to the flywheel effect, that's not as simple as that. The only thing working in favor of the idea is the larger diameter of the clutch vs. the flywheel. Beyond that, the rotating inertia of the clutch is very significantly reduced by the fact that it rotates at about 40% of the speed of the engine (speed is an exponential contributor to inertia), and by the fact that it has to deliver any inertia it may have to the crank through the disadvantage of a 260% overdrive ratio. There is surely some small additional effect, but it's very much diminished by these factors.

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  • WB450

Posted March 18, 2010 - 09:50 AM


Thank you.

  • Just_a_trail_rider

Posted March 19, 2010 - 09:32 AM


I had a 13oz fww on my yz250 and I got rid of it when I got the rekluse.

My thoughts are that the rekluse is really good for preventing you from stalling. It will do this with or without the fww.

Sell it a get a few bucks. Ride as if you do not have the rekluse and let it help you. Stay agressive, stay on the gas and don't become a lazy rider who depends on the rekluse. Fan the clutch when you are supposed to or feel the rpms dropping to low. Stay in the correct gear for the situation.

If you depend on rekluse to work your cluch for you all the time, you will quickly notice the excess heat and will feel the clutch start to fade.

  • grayracer513

Posted March 19, 2010 - 10:08 AM


A YZ250 (or your WR) is a much different engine than a YZ450. The 250 has a relatively heavier flywheel installed on it from the factory than does the YZ450, and the 450 has so little rotating inertia that its lack of flywheel effect becomes quite noticeable below 3500-4000 rpm, never mind any really low speeds. Even disregarding the stalling issue entirely, the performance of the engine at around 2500-3000 is so improved by the addition of 8-10 ounces of weight on the tiny flywheel that no one could fail to appreciate it unless they just never ride the bike in that rev range. Rekluse or no, use the weight. The bike really should have been built with it.

  • shrubitup

Posted March 19, 2010 - 10:17 AM


And that's the final word.

I agree with mauricedorris for the YZ250 but that's another topic. :banana:

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