Do i have a flywheel weight or not?

[motocrossbubba]

I keep my bikes cleaner than my self i got a fly wheel weight too idk what size it is tho

[LoKi]

Originally Posted by Logik

it was previously owned by GNCC rider Barry Hawk.

According to Steathy's website Hawk uses their products.

The Steahly weights bolt on and don't require being welded. If at one point there was additional weight on the stock flywheel, there isn't one on there now. That's stock. You can even run the part number of the side to verify.

[Logik]

Originally Posted by LoKi

The Steahly weights bolt on and don't require being welded. If at one point there was additional weight on the stock flywheel, there isn't one on there now. That's stock. You can even run the part number of the side to verify.

well see thats funny because i made it over to my friends house tonight and we took off his ignition cover...

this is stock...


this is mine:


both are 2000 yz250's

[Logik]

Originally Posted by MotoMan

Hmmm....I think if I were you and were concerned about it, I would try and get ahold of Mr. Hawk. Did you buy the bike from a dealer or right from him?

Bought it from a friend, that owns a car lot. Apparently Mr Hawk traded his bike plus some $ for a car. Then my friend said it's too fast and buys a honda thumper (250cc) and offers me this bike for an awesome price.

Originally Posted by motocrossbubba

OMFG that thing runs? my god

i know. i know. Im a neat freak but it hasnt stopped snowing lonmg enough to clean the bike up. i have a list of stuff i need to do when it stops being so ****ty out.

[psycho393]

I'm betting that Yamaha had a change in the run of their flywheels. And that both you and your friend have stock weights.

[Vintage Dave393]

That's a welded-on weight. The diameters of the flywheels are different and yours is a larger diameter. That will increase the moment of inertia and add to the feeling of having more weight. Looks like a Zip Ty add on to me.

Yamaha (and all of the Japanese) builds each model in a continuous run down the assembly line so I doubt that they used different suppliers or subsituted parts. Now the European manufacturers.............

[LoKi]

Originally Posted by Logik

well see thats funny because i made it over to my friends house tonight and we took off his ignition cover...

this is stock...


this is mine:


both are 2000 yz250's

You can see the same part number on both flywheels in these pictures. F5CU-10. They're both stock.

[mtk]

No, the top one is stock, as evidenced by the gold anodizing. The bottom one is a stock flywheel with a weight welded on it, as evidenced by it's larger diameter and lack of anodizing. VintageDave is quite correct in his assertions that Japan Inc. does not use an assortment of parts to build one bike. I've also never seen a Japanese bike with a flywheel left raw and unfinished like that. They're always coated in some manner. Now I'm sure someone will produce a photo of the latter to prove me wrong, but the fact remains that the bottom one isn't stock. It will have a different moment of inertia than the top one and that isn't kosher to the Japanese engineers who designed it.

Look at the lower flywheel closely. You can see a "ring" in the middle of the machined portion of the outside where the original flywheel ended. It's not very pronounced, because that was the weld zone, but you can see it.

[Silver_Fox]

Take both yours, and your freinds flywheels off. Weigh them....... you will know exactly what you got.

[LoKi]

Originally Posted by mtk

No, the top one is stock, as evidenced by the gold anodizing. The bottom one is a stock flywheel with a weight welded on it, as evidenced by it's larger diameter and lack of anodizing. VintageDave is quite correct in his assertions that Japan Inc. does not use an assortment of parts to build one bike. I've also never seen a Japanese bike with a flywheel left raw and unfinished like that. They're always coated in some manner. Now I'm sure someone will produce a photo of the latter to prove me wrong, but the fact remains that the bottom one isn't stock. It will have a different moment of inertia than the top one and that isn't kosher to the Japanese engineers who designed it.

Look at the lower flywheel closely. You can see a "ring" in the middle of the machined portion of the outside where the original flywheel ended. It's not very pronounced, because that was the weld zone, but you can see it.

The bottom one looks exactly the same as the stock flywheel on my 01 KX250. Minus the rust of course. They're both stock. If anything it may have been lightened.

[mtk]

It's not stock, period.

The fact that it looks like your KX doesn't mean diddly since this is a Yamaha, not a Kawasaki. I could pull the cover off of my Maico and tell you what that flywheel looks like, but that wouldn't answer the question either. It's called irrelevant information.

Look at the location of the screw in the upper-right corner. See how it is closer to the lower flywheel than the upper one? The lower is clearly larger in diameter. It has had something welded to it and the weld area has been machined afterwards. You don't make something larger in diameter to "make it lighter." I'll bet my two engineering degrees on it. Yamaha also is not in the habit of making two totally different parts for the same bike rolling down the line.

Even Steahly agrees with me.

Originally Posted by Logik

I received an email from Steathy Offroad and they claim that there IS a flywheel weight installed and that it is "probably welded on"

[Jeff172]

I have never seen a stock Yamaha flywheel that looks like that one. I've had about 12 Yamaha's in my life.

Also, my main reason for this post is, ALL flywheels are weighted. Yes, even stock ones are. Even when you buy an aftermarket they show them as stock + 3oz, 6oz, etc. If they were perfectly balanced with no weight, the bike would stall immediatly when the clutch was pulled in.

Now you can argue that all you want, but the fact is ALL stock flywheels are weighted, be it 1oz or whatever your brand, year, and size is. I just read an entire article about this.

[LoKi]

Originally Posted by mtk

It's not stock, period.

The fact that it looks like your KX doesn't mean diddly since this is a Yamaha, not a Kawasaki. I could pull the cover off of my Maico and tell you what that flywheel looks like, but that wouldn't answer the question either. It's called irrelevant information.

Look at the location of the screw in the upper-right corner. See how it is closer to the lower flywheel than the upper one? The lower is clearly larger in diameter. It has had something welded to it and the weld area has been machined afterwards. You don't make something larger in diameter to "make it lighter." I'll bet my two engineering degrees on it. Yamaha also is not in the habit of making two totally different parts for the same bike rolling down the line.

Even Steahly agrees with me.

You're comparing apples to oranges. Where as I was comparing oranges to oranges. Your Maico in german. However, my kawasaki and his Yamaha are both Japanese. Believe it or not, there is a correlation. Where as your Maico has none. I was refereing to the top picture when I said it may have been lightened.

Steahly weld on weights go over the exterior of the existing flywheel, and don't change the circumference. Thus making the thickness of the weight greater. Trust me. I just went through this with Steahly. I just added one of there weights to my bike. Easiest way for him to tell if there was a weight on it is if there's a spacer for his case cover.

I don't doubt your engineering skills. Just stating from my experience. Also one could be OEM and the other isn't. Both weights have the same numbers. The 10 I would assume means oz's.

[Vintage Dave393]

That's not a Steahly add-on though. More likely it's from Zip-Ty. The area inside the add on is the definately the same. The weld on wouldn't have to be that much heavier due to the increased circumference which would add to the moment of inertia. Weight is not the only critical item for a flywheel. Position of the weight can make it feel heavier or lighter to the rotating mass.

I don't know if the flywheel is heavier. Whoever said take them off and weigh them was on the right track. I do know that it is not a standard flywheel and has been modified in someway.

I guess the more important question is does the bike do what you want it to do or do you need to make changes to suit you.

Here's a photo of the Zip Ty weld on. It looks like a heavier version, but you get the image.

[mtk]

Originally Posted by LoKi

You're comparing apples to oranges. Where as I was comparing oranges to oranges. Your Maico in german. However, my kawasaki and his Yamaha are both Japanese. Believe it or not, there is a correlation. Where as your Maico has none. I was refereing to the top picture when I said it may have been lightened.

Steahly weld on weights go over the exterior of the existing flywheel, and don't change the circumference. Thus making the thickness of the weight greater. Trust me. I just went through this with Steahly. I just added one of there weights to my bike. Easiest way for him to tell if there was a weight on it is if there's a spacer for his case cover.

I don't doubt your engineering skills. Just stating from my experience. Also one could be OEM and the other isn't. Both weights have the same numbers. The 10 I would assume means oz's.

No, I'm comparing apples and oranges and you're comparing them to tangerines. Closer, yes, but still irrelevant. And no, there isn't a correlation since Kawasaki thinks parts like this shouldn't be corrosion-protected, while every Honda and Yamaha I've been inside has been coated in some manner, like it should be. But you're correct in that there is one correllation between them: no way on earth do two of the same model have radically different parts like that and still have the same engineering or part number stamped on them. It's just not done like that with any Japanese manufacturer. I'll bet you'll find those same numbers on the one VintageDave just posted.

As VintageDave said, it's probably not a Steahly. They're not the only game in town.

It's also not lightened. You do NOT increase diameter in a lightening operation. If you're going to make it lighter, you don't fire up the TIG welder at all, because it increases the rotational inertia of the part, which is what we're really after in the first place. It just so happens that adding mass is the quickest and easiest way to increase the moment of inertia of a part, so you hang some more metal on it. If you want it lighter, you skip the welding operation and move on right to the lathe work. You can clearly see the different materials in one of the photos and that "line" is clearly in the right spot to match the profile of the stocker above it. The one Dave posted is an even heavier version than the one on the bike.

A spacer on the cover also is NOT a tell-tale sign. For example, only half of the Steahly bolt-on weights for my CR250 require a spacer. By adding mass in the manner they did, I'm quite sure it will fit under the stock ignition cover, which was part of their plan. Spacers add gaskets and extra gaskets give extra spots for leaks to develop.