ruffstff

Member
Mar 27, 2004
9
0
I need to tone my bike down a bit, 2004 yz250 so i am about to purchase a 13oz flywheel weight. I pretty much a beginner so i want the heaviest flywheel weight possible. Will there be a dramatic affect on the bikes hit with this heavy of a flywheel weight, if not, what else can i do to the bike to make it easier to ride. Oh yea im gonna be doing mostly trail riding, no track riding at all. Im 5'10 5'11 210pds, thanks guys
 

epatt

Member
Aug 18, 2003
8
0
The 13oz weight is a nice smooth power delivery. But this bike WILL still have a huge amount of power in the woods. What the weight will help is keeping rear tire from spinning up and trying to pass the front everytime you give it gas. It will also let you lug it a bit more without stalling as easily. I had a 13oz first and went to a 11oz. There was nothing wrong with the 13oz at all I just went to the 11oz because it was what I originally wanted for the bike but was out of stock at the time. The bikes powerband will still be the same it will just be more controllable and tractible. As for detuning the hit I am not sure the best way to do it. It will never be smooth like a ktm250 exc or anything but man it will rip on the straights when those wont. You can change the powerband with pipe/silencer combos but I am running stock so I dont know which would be best. You could also try some porting work by Eric Gorr, I think he can shape your power the way you want, but I personally have never tried it.
 

blanc

Member
Dec 18, 2002
623
0
I have just put a 13oz on my honda cr250, i think that you will be very happy with the result! You will seem like you are going faster as the rear wheel is not spinning as much the power is way easier to control!
 

jho410

~SPONSOR~
Apr 30, 2002
272
0
I have the 11 oz on my 01 YZ250 and wish I had gone with the 13 oz. I ride all trails.

If that 04 YZ250 doesn't work out for you, I'll take it :yeehaw:
 

KaTooMer

~SPONSOR~
Jul 28, 1999
435
0
The flywheel weight makes it so it doesn't rev quite as quickly, which helps you feel like you're more in control of the back wheel. And with more weight, there's more inertia being driven by crankshaft which means the engine doesn't come to a stop as quickly when you pull in the clutch (i.e. less stalling...and I'm sure my physics terminology isn't completely correct, but the concept is, I think). I use an 11-oz weight on my KX. People who ride KTM 4-strokes (and sometimes the 2-stroke off-road models) complain about it stalling even with the flywheel weight, but it doesn't bother me. It's still got a hell of a hit and I like that bike more and more each time I ride it.
 

Chief

~SPONSOR~
Damn Yankees
Aug 17, 2001
682
0
I put the 13 0z on my RM and it does make a difference, but not what I expected. Not as big a change. I can wheelie much easier now without it flipping over, I noticed that immedeately, And it will Lug down lower without stalling, but I'm either downshifting or feathering the clutch before I hit that point anyway. In that aspect it will help keep you going when you are gonna stall the engine on a long steep twisty hill that takes everything out of you. It's a nice addition and I would do it again. I guess because I'm a spode, don't race, and ride a lot of tight woods, it was a sensible mod to make for me.

If you really want to tone your bike down you can loosen up the preload spring on the powervalve (exhaust valve). It's an external adjustment and only take a few minutes to accomplish. I think your bike will have the adj. externally.

Mine was set stock at 90 deg clockwise from zero tension. I've had it set at zero tension and 45 deg clockwise. Both made the bike run a lot flatter for low rpm woods, less tiring with still plenty of grunt. You can set it however you like and adjust it as you go. It WILL make a big difference if you want to tone it down and costs zilch. Look it up in your owner's manual and see what you can do. It could be the ticket.

Now with the weight on and 2 yrs riding behind me I have the PV set to stock. It comes in handy where I only have a short distance to pick up a lot of momentum and speed. You will eventually end up setting it back to stock with some time too.

Please Update whatever you do as I'd like to know what happens and your impression of the FWW and/or PV adj.

Chief
 

marc_w

Member
Apr 2, 2004
41
0
I've got a 12oz on my '00 RM250, and there is very little difference besides that it's slightly less likely to stall when I screw up in the nasty stuff. I still screw up, and it still stalls.

It still hits as hard as ever, and rev's as quick as I need it to...
 

Rcannon

~SPONSOR~
Nov 17, 2001
1,886
0
I have a 6, 8, and 10 oz kit that fits my YZ 250. There is not agreat deal of difference between any of the weights.

It is an excellent product, but the small weight changes do very little for the power characteristics. The 6 is difficult to notice. The 10 oz makes it easier to follow my nephew around on his xr 50. Once the powervalve opens, the bike feel fast no matter which size is on. I also get better tire life with the weight on.
 

blanc

Member
Dec 18, 2002
623
0
I tried out my Honda cr250 yesterday with the steahly 13oz for the first time,
I rode tight single track woods....did not stall and made it like a tractor. Still v powerfull.
I then rode flat out field riding...drag racing!! It made it very fast in a straight line, the rear wheel did not spin as much, it was easier to control and great fun. I would not think i would be faster on the mx track without it, but will let you know on monday!
 

Chief

~SPONSOR~
Damn Yankees
Aug 17, 2001
682
0
The more I see on this board about flywheel weights, the more it seems that the amount of effect a weight has on your bike depends on what bike you are modding.

My bike for instance has very little crankweight to start with and the weight had minimal effect whereas owners of other makes, models, year, report significant changes.

Just an observation.

Chief
 

jducati

Member
Dec 11, 2003
18
0
I just ordered a 12 oz. for my 1999 CR250, I will see what the improvements are, my friend has a 12 oz. on his CR and loves it. I was also thinking of going up a tooth on the front sproket, I think that will help for woods riding also, will not have to shift as much as stock gearing.
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
jducati said:
I was also thinking of going up a tooth on the front sproket, I think that will help for woods riding also, will not have to shift as much as stock gearing.

IMO, adding one tooth on the countershaft will be more change than you want. I would recommend keeping your stock 13t front and replacing the 50 tooth rear with a 49 or 48. I run 13/49 on mine, and even the small change lets you hold gears noticieably longer, for less shifting.

BTW, I think you will like the flywheel weight alot. Mine has an e-line system, which adds approx. 12 ounces. With a V-force reed block, FMF Turbine Core silencer/spark arrestor, the '99 CR has great low end for a 250 two stroke.
 

Chief

~SPONSOR~
Damn Yankees
Aug 17, 2001
682
0
I agree with Dave, countershaft sprocket makes too much of a difference in either direction. Changing the CS can create more problems than going up or down 2 teeth on the rear. Going bigger on either sprocket is better for your chain and sprockets (credits to Jaybird)

Also remember, once you are out of first you won't feel any difference since your 'gearbox' still has the same ratio gear to gear. You'll only feel it in 1st and last gears, but it's a good idea, I never thought about going up a tooth in ft or down in rear for woods. Gearing higher with sprockets, that would prolly gimme too tall a first gear. It's not going to widen your shifts.

Joe
 

marc_w

Member
Apr 2, 2004
41
0
For the stuff I ride, I needed to drop a countershaft tooth. (from 13/48 to 12/48). I even ran 12/50 for some time.

The 12 was eaten up pretty fast though - I won't run one again. I'm now running 13/52 (same as 12/48) and I'm pretty happy with it.
 

yz138

Member
Feb 16, 2004
6
0
Chief, that preloaded spring you mentioned, is it on the left side of the cylinder and has two screws on either side of the circle plate. Are the screws loosened then turn the circle plate with the notch on it. Please let me know

thankyou
 

Chief

~SPONSOR~
Damn Yankees
Aug 17, 2001
682
0
Yes YZ,

That's the way it is on my bike. When you loosen the 2 nuts, pay attention to which direction the knob returns to. I would try somewhere in between where it was set before you loosened them and zero tension (where the knob returns when you loosen the nuts).

Joe Chief
 

sunnyboy

Member
Feb 24, 2003
98
0
the flywheel should work well for your needs,sounds to me that you need to also get more seat time,with that and learning how to use your right wrist with more control you will get it all together and have more fun the more you ride
 

Lorin

LIFETIME SPONSOR
Jun 25, 1999
948
0
My riding partner has an 03yz with an 11 oz flywheel and a pro circuit pipe, and he rides it as a woods bike. I have spent time on another 03 yz with a fatty pipe (no weight), and would say that the flywheel weight helps considerably with that motor. I would also have to say that I prefer the pc pipe to smooth out the midrange hit of the 03 \ 04 motor, as well as having a little more over-rev than the FMF.
 

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