Flywheel weight on 125cc?

[KawiRider]

I am thinking about adding a heavier flywheel weight to my YZ 125. Is it really worth it? I ride in the sand in South Jersey. Will I notice a big difference? Is it worth buying? What oz would you recommend? Your replies are very appreciative.
-Thanks

 

[duke]

I would not recommned it. Many folks confuse the premise behind the installation of fly wheel weights. They dont enhance bottom end power per se. What they do is take the hit or abruptness of power being transfered as the engine RPM increases. Dont forget, a 125, was designed to operate in the upper RPM level. Its ability to move is motivated by its ability to reach a RPM very quickly. You will be robbing the bike of its ability to achieve by adding the restrictive weight of a heaviwer fly wheel. If more bottom end is what your looking for, then consider a change in reeds, gearing or a pipe. Do a check on this sites search engine and enter flywheel weight. You will see others, who like you made quiries about the installation of a fly wheel weight. l

 

[MN KDXer]

I'd suggest to consider using the FWW. My son (AA enduro rider) ran his 01 RM125 with a 7oz Steahly last year, and was very happy with the results. It adds some low end power (which, granted, there is not a lot of low power on a 125), a tad softer hit, smoother power to make the bike more controlable in slick conditions, and seems to boost the overall power delivery.

Granted, we ride mostly off road, but he feels it would be worth while on a MX track.

If you're not sure of which size for your application, call Steahly and talk to Chuck; he's really knowledgeable of what size weights are appropriate.

 

[KawiRider]

MN KDXer,
What work did your son have done to his bike to make it more woods ready?
-Thanks

 

[MN KDXer]

KawiRider,

In addition to the FWW, we installed Boyesen reeds, which were not quite as effective on the 01 as his previous 99 RM125. This year he is trying the V Force reeds.

Also, the gearing was changed from 49T rear to 51T. Last, the suspension was revalved by Trak Control.

Another thing to add for off road, is a skid plate. Besides saving the engine & frame tubes from smashage, the skid plate helps the bike slide accross those muddy ridges w/o digging in.

 

[Coach in ND]

What year YZ are we talking about here?

Coach

 

[ChadLac1984]

I haven't personally added weight to my flywheel on my cr125, but have been thinking about a heavier flywheel as well. I would imagine for a 125 if your a good rider who can stay on the pipe and keep your RPM singing high . You would have to have a gain bottom and top because of a larger rotating mass , only if your rpm is high enough. Plus when your getting tired at an end of a moto and maybe it's harder for some people to use their clutch , it we'll help you from stalling in corners . If I had the money and time I would r&d a lot and put a lot of different combos together . Just sayin