Fly WHEEL WEIGHTS

[GREENHORNET]

I was woundering do you need a fly wheel weigth?
How many of you rides ride with one on.

 

[KnoxKDX]

Flywheel weights cause the engine to rev slower and alter the power curve giving you more low end. It is a great mod if you have a KX or YZ you want to adapt for the woods, but really no need on the KDX...you would take a big hit on top end.

 

[andrew]

I disagree, the flywheel weight does help on a KDX, if you have even some of the mods that are common. Porting, piping, rejetting, carb mods, reed valve upgrades etc will all give you a fair bit more performance, often at the expense of the renowned stock bottom end. A flywheel weight will transfer some of that additional power back to the bottom and aid traction by reducing wheel spin and improving engine momentum. It doesn't significantly alter top end performance at all. Try one if you have a modified bike - you may be surprised! and...you can remove it whenever you like.

Cheers,

 

[canyncarvr]

I've got one. There's no loss on the top end that is discernible. The physics of the thing 'say' you'll get less wheelspin. The more power to the ground, the better. Even WITH perfect traction, a FWW would slow down the 'loop-it' syndrome.

I primarily like it due to its benefits on downhills. The kdx KEEPS going much better. No tap of brake at the wrong time (or too much tap) will kill it.

Need? Probably not. Nice? Yep!

 

[KnoxKDX]

I was just going off my past experience with the mx'ers I've had...so bottom line is now you have several opinions.

 

[GREENHORNET]

Thanks guys- truth is that i have had a fww since the beginning and was just wondering what others have to say- i have also had kx 250 an i put a fww on it, like you say it dose it cuts the RPMs down so its more rideable
So you think i should keep it on? I have rb mod on it now and fmf pipe an silencer,boysen rad valve- i may try it once with it off. That RB carb is a real kick in the pants, i never thought my green machine could move so quick Thanks for the good input

 

[canyncarvr]

As you say...try it on/off and take your pick.

re: RB carb. I believe you said you have the CEK/L needles, and you're using #3 clip? Give the CEK a try on #4.

Cheers!

 

[GREENHORNET]

canyncarvr- So moving the clip down to 4 thats going to lean the bottom end up- what do you normally ride in woods or sand once it gets warm again i'll try that I'm always open for for ideas I am jusl learning how to jet thanks keep me posted

 

[fuzzy]

"Flywheel weights cause the engine to rev slower and alter the power curve giving you more low end. It is a great mod if you have a KX or YZ you want to adapt for the woods, but really no need on the KDX...you would take a big hit on top end."

It seems others have answered your question just fine, but let me clear up some things here. A FWW will do nothing to your engines power characteristics(IE when looked at on a dyno). They are made to add weight to quick revving engines to calm their 'snappy' characteristics. You want this snap on a MX bike, but might not want it in the woods. The biggest reason for added FWW is to keep the engine lugging at low rpm's. Think of having more FWW as opposed to less in the terms of a bicycle tire. A FWW would be like filling your tire w/ lead. THe power of your legs will not change by doing this. You will be slower to get going, but will hold your momentum much better. THis directly relates to FWW. More weight at the out edge of your reciprocating mass will give the entire resiprocating assembly more 'momentum' so to speak. They do a good job of smoothing out idle as the momentum forces the enging to keep turning over and fire.

The KDX already has a decent amount of FWW, and when combined w/ a granny 1st, and KIPS I've never desired to add more weight. I consider more FWW a necessity on a MX bike that will be used in the woods. IE KTM MX/EXC's come w/ more flywheeel weight then the SXC. In fact tank size, and FWW are about the only difference betweeen a MXC, and SXC. Kawi has already added FWW on the KDX for you, but more could be added as a preference.....

My 2c

John

 

[KnoxKDX]

[QUOTE A FWW will do nothing to your engines power characteristics(IE when looked at on a dyno). They are made to add weight to quick revving engines to calm their 'snappy' characteristics. [/B][/QUOTE]

John, I appreciate you comments, and you are correct. I guess I worded my answer poorly, but looking at an rpm graph on a time chart is really what I should have said. And if you line up to race a guy with the same bike in a straight line and he doesn't have weights, he's gonna win everytime, because it does take you longer to get up to speed.

 

[flarlee]

Would a front and rear sprocket change have the same effect if you put more teeth on the back 49 to a 51.

 

[GREENHORNET]

FLARLEE --i HAVE BOTH A FWW AND 13/51 GEARING-
1ST GEAR IS VERY LOW AND I DON'T USE IT UNLESS I'M IN THE WOODS

 

[Tom Ludolff]

How much does a flywheel weight cost ???

 

[GREENHORNET]

toM I PAID $100 STEAHLY MAKES THIS CALL AND GET A CATALOGE 1-800-800-2363 IT EXPLAINS THIS MOD-- OR JUST ASK YOUR DEALER ABOUT IT THE FWW IS REALLY EASY TO PUT ON

 

[Tom Ludolff]

Thanks GH!! I hope I can find one cheaper than that. It seems like alot for just a weight. Like it should be $15 or $20. Wishful thinking I guess.