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Flywheel mounting

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Hey guys,

since we dont have suppliers for flywheels in Germany and my friends work for several CNC companies we want to machine some flywheels by our own.

The big question is:

How to mount the weight securely to the OEM flywheel?

Can anyone explain or (would be perfect) show some pics of the mounting mechanism?

Thank you very much

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Someone else also wanted to do this - make their own flywheels, although they posted in the ENGINEERING & TECHNOLOGY sub forum. There's so much involved in correctly constructing a flywheel with the tapered center made of a different grade of steel, properly hardened, securely fastening a curved magnet (where do you get those???) to the outer shell which is usually riveted to the center. After a dialog pointing out the details that HAD TO be perfect, I believe they thought better of the project. Not that you CAN'T do it. Just be aware going in there's a lot to it that the manufacturers worked out decades ago.

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Oh. OK, that's a little easier. How about buying one off of ebay and copying it. (Is that legal? Probably OK if you're not selling quantities of them.) You'd have a little money into it but you'd certainly have the dimensions settled. Many ebay sellers ship world-wide. As for changing weight of a particular flywheel, the farther from the center, the more a specific weight provides inertia so it will be more effective. Some bikes have a problem with space with the side cover being very close. Sometimes, they sell a thick gasket or a spacer to get some clearance back. I think you could do it!

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I see your point and I already thought about various mounting options.

My friends and I are kinda technical freaks. We mounted a CRF steering damper on my YZ frame, machine suspension parts and so on.

I just wanted to know how the stealty or similar flywheel weights are mounted to the existing flywheel.

For reasons of true run I think the best way will be to mount it on the crankshaft assembly and not on the flywheel itself.

Edited by Vietze

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Keep in mind there's not much crank shaft available to do anything with although some FWW's do sneak it behind the nut. I'd study some photos of the FWW for the bike you want to make it for. Again, Steahly has been thru the R&D and if they mount a certain one a certain way, that's probably the best way (or the only way) to do it.

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My friends and I are kinda technical freaks.

I'm just making it now. But, it's not only for the flywheel. The primary purpose is accurate fixation of the magnet for a like E-Line lighting coil.

E-line magnet or any additional flywheel weits make the decentration of mass and shape. It's not acceptable for me,

magnet_zps14ef1a81.jpg

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Hey,

very interessting.

Could you please go into detail a bit more. Its my first time messing with flywheel weights.

The left one on your pic looks like the OEM with additional weight. What about the right one?

Decentration means that the weight is moved more to the left side affecting the handling of the bike?!

EDIT:

Do I see it right that the right one is your modded version and you use a different nut to fixate it to the crank?

You removed the stock weight and machined a different one?

Have you clenched it like stock or have you used bolts?

I'm just making it now. But, it's not only for the flywheel. The primary purpose is accurate fixation of the magnet for a like E-Line lighting coil.

E-line magnet or any additional flywheel weits make the decentration of mass and shape. It's not acceptable for me,

magnet_zps14ef1a81.jpg

Edited by Vietze

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Yes. I lathed outside of OEM to make accurate circularity and measurement. And I made weight ring with gun metal.

The inner diameter of weight ring is lathed to -0.05mm for the outer diameter of processed OEM flywheel.

They are fixed by shrinkage fit and epoxy.

flywheel00_zps3bf76069.jpg

Decentration,,, Sorry, because my specialty is medicine chemistry, I don't have enough knowledge about engineering technical term in English.

That I want to mean is the offset of balance on rotator.

All addional weight are fixed without enough consideration of rotation center. It makes unfavorable vibration and reduce the durability of the bearing.

If you set a dial gauge to addional weight and rotate the crank, the needle of the gauge will make you have dizziness. :)

It may be a trifling problem practically. However, I can not think, it is appropriate to attach such a thing to the crank that adjusted with 3/1000mm precision.

And more, about E-Line lighting coils, it somtimes comes a more serious problem.

The offseted magnet conflicts with core of coil and harms it. It is based on my own experience.

The right one is the magnet for E-Line like lighting coil. It made from a magnet for Ducatti and brass.

magnet2_zpscea08764.jpg

They are fixed with epoxy too. And it processed to fit to the flywheel with 0.05mm clearance and they are fix by special nut that you can see at 1st picture.

Of course the magnet is not the element which is necessary as the flywheel weight.

Too much angular momentum affect to the handling as you know. I'll adjust it optimally with riding. It is easy to reduce mass.

E-Line00_zpsfcead1ee.jpg

My primary purpose is make up this one. It's under construction.

But, if you think about this concentric issue, you may not avoid some processing of OEM flywheel.

Edited by kmtr
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I have a spare flywheel for my bike. We will see what we can do!

Thanks a lot mate, helped a lot!

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I see your point and I already thought about various mounting options.

I just wanted to know how the stealty or similar flywheel weights are mounted to the existing flywheel.

For reasons of true run I think the best way will be to mount it on the crankshaft assembly and not on the flywheel itself.

http://www.steahlyoffroad.com/skin/frontend/default/steahly/PDF/YZ-250-02-10-flywheel-weight-installation-instructions.pdf

The center threads onto the crank and 4 set screws hold onto the flywheel.

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