GYTR MX Flywheel. pros/ cons ,advice ?

35 replies to this topic
  • ekulb14

Posted October 04, 2013 - 06:43 PM


So im thinking about installing a heavier flywheel, first question is how is the bike affected in practical terms?Im no racer just out to have fun maybe C class skills on a good day.


Im all about being as smooth as possible riding a 450 at 125lb thats harder than it sounds. Dont get me wrong i love my 450 just wondering if smoothing out the power will help in my situation.


 Secondley, ive watched/ read up on the install and it seems pretty simple. Ill buy a flywheel puller but is there anything else ill need any tips or words of advice?


These guys seem to make it look easy enough.




  • sacfelix

Posted October 05, 2013 - 12:40 PM


You will need a 5/16 socket, ratchet and a puller. It only takes about 10 minutes to swap it out. It really is that easy.

  • WouldsAssassin

Posted October 05, 2013 - 02:20 PM



Edited by WouldsAssassin, October 05, 2013 - 09:52 PM.

  • Yzflier977

Posted October 05, 2013 - 03:11 PM


Curious to see the replies. I've been thinking of doing this myself.

  • WouldsAssassin

Posted October 05, 2013 - 03:12 PM


At yours and most riders skill levels there are no cons to a heavier flywheel.

  • Hoosier-Daddy

Posted October 05, 2013 - 06:43 PM


Just put the gytr 9 oz on my yz450f. Experienced less stalling in tighter, slower trails. Bike is less jerky. Seemed like hills were easier too. Not sure about how it affects the track experience but great mod for the woods. Im not a big person either, anything that makes it easier to ride is a plus.
It was easy to install. Mine came with a new gasket.

  • grayracer513

Posted October 05, 2013 - 09:37 PM


At the time that I installed the GYT-R 9oz on mine, my son and I each had an '06. Before and after the flywheel, they ran dead even side by side on pavement. Mine lost absolutely nothing with the swap. Nothing.

The gains were as mentioned above. If you ask me, it should have been built that way to start with.

  • Decreasing Dave

Posted October 07, 2013 - 06:05 AM


I put the GYTR "Performance" flywheel on my '06 some years ago.  It's not the "offroad" flywheel, which is the heavier one.  This is the one that supposedly Chad Reed was using on his racebike at some Supercross venues for better traction out of the corners.


Anywho,  my bike "felt" like it gained 10 hp from the flywheel (Disclaimer:  Flywheels DO NOT add any HP to a motor.)  Fact is, with the tire hooking up better, the acceleration was so very much improved, it felt like it had more power.


I did it because I was running some tighter trails at the time and was spending a lot of time on my clutch trying to get the motocross beast through them.  The flywheel definitely helped.


Back to the present, because my boy (9 y.o.) is racing motocross, I ride a lot of tracks these days.  I find that the flywheel helps a bunch here too especially when the track is a bit slick or for basic drive out of a turn (just like Chad Reed did I guess).  I ride the Dunes as well.  I like it there because if I have to, I can lug the bike a bit more and the flywheel helps me pull out of it.


All Pros, No Cons.



  • grayracer513

Posted October 07, 2013 - 08:16 AM


(Disclaimer:  Flywheels DO NOT add any HP to a motor.)


The truth is that they actually do, but only in the very low RPM range.  When the engine is loaded at low speeds it is slowed by each of its own compression strokes and has to recover that out of the next successive power stroke.  If more rotating mass is added, the inertia remaining from the previous stroke reduces the loss, and there is a small net gain in output in the lower part of the functional speed range.  If the weight added is not so great that it becomes an impediment to engine acceleration, you come out ahead.

  • Yzflier977

Posted October 07, 2013 - 05:31 PM


Okay I'm sold. This will be the next mod done to the '09. Good imput guys, thanks a bunch. This thread is why everyone should be on thumper talk. The sharing of knowledge and experiences can be invaluable.

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  • firejosh

Posted October 07, 2013 - 09:14 PM


Invaluable is right.  I am reading this thread thinking about adding one to my 08...ok I'm sold now!

  • gofaster450

Posted October 08, 2013 - 01:46 AM


Agreed with all the above. Installed the Stealthy 9oz weight on my 12 and it the bike very tractable in technical conditions and improved the handling (front end felt more planted when on the gas). No regrets for off road riding in Georgia (hard dry dusty clay when dry, slippery, snotty when wet) and easy to install.


Posted October 08, 2013 - 07:43 AM


All pros for me no cons --- I have the heavier "off road" GYTR --- if your gonna do it  - "go big".



The truth is that they actually do, but only in the very low RPM range

Love the feel of that!

  • rdefonce

Posted October 08, 2013 - 08:45 AM


Agreed with all the above. Installed the Stealthy 9oz weight on my 12 and it the bike very tractable in technical conditions and improved the handling (front end felt more planted when on the gas). No regrets for off road riding in Georgia (hard dry dusty clay when dry, slippery, snotty when wet) and easy to install.

Wow I didn't know that heavy of a FW was available for the FI Yamaha 450's engines!

I added the GYT-R 4.3 oz extra weight FW. That was nothing but goodness for my '10 450F.

  • grayracer513

Posted October 09, 2013 - 06:35 AM


Because the '10 and later EFI bikes have a much larger diameter stator/rotor, the addition of a smaller amount of weight makes a bigger difference in the inertia mass of the flywheel.  4 ounces on the late ones does more than 9 on the older models.

  • SAthump

Posted October 09, 2013 - 06:39 AM


Stealthy markets a "9oz" weight for the newer engines
I'm not sure how it compares to the gytr 4.4oz, which I have and like.

  • flapwick

Posted October 09, 2013 - 08:48 PM


I added a 9oz GYTR flywheel to my 07 450 and I love it.To tell you the truth,I think the next heavier one(11oz?)might be even better.I am a 52 year old moto only novice.Definitely smoother and less prone to stalling.

  • ekulb14

Posted October 12, 2013 - 11:34 AM


ok cool thanks for all the responses, deffinatley going to move ahead with this mod. Now im just wondering if i should go with the heavier 9 oz over the 4.

  • grayracer513

Posted October 12, 2013 - 11:49 AM


Speaking from experience, the lighter plus 4 flywheel is a waste of time. On the '03- '05 or '06-'09 models, it barely has any noticeable effect. Go with the plus 9. You'll love it.

  • firejosh

Posted November 20, 2013 - 07:24 PM


Just put a 9 ounce GYTR fw weight on my 08 YZ450. Love it. Much more tractorable power. Thanks for the recommendation guys.

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