C-model flywheel repair using a later kdx flywheel

Discussion specific to the various air-cooled KDX models sold in the USA
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kawagumby
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C-model flywheel repair using a later kdx flywheel

Post by kawagumby »

I found a post in the general discussion forum where one of our KDX'rs included a picture of the flywheel and stator plate modifications done by Jeff Fredette.
The flywheel provided appears to be an H model (based on the numbers stamped on the housing) and the stator mod is simply relocating the mounting slots to sync the coils with the H model magnets. The late model flywheels are not modified for this stator fix. See the following post for the flywheel mod using an unmodified stator assembly.

I'm assuming the pictured coils aren't modified (the ignition coil looks like a Ricky Stator replacement unit) and the distance from center is the same - and since we now know that simply rotating a later model flywheel on its hub also nets a successful fix, we know that the stock coils will work with a later flywheel.

Based on more corroborating information recently found regarding the alternative flywheel modification (see next post), it appears that the stator mounting hole locations are close to a 90 degree change...the picture may not portray that well, but if the flywheel fix is truly a 90 degree rotation the alternative stator relocation should also be 90 degrees. Using a 87 stator in hand, I marked where the fredette modified stator mounting slots are relocated, and it is close to 90 degrees (rather than center of the slot the 90 degrees occurs at the leading edge of the slot when measured clockwise from center of existing slot).

So, there may be a slight difference between the two fixes (assuming the flywheel rotation fix is actually exactly 90 degrees)... which one is best is your guess.

Those who may be inclined to do so can blow this picture up and give it a try....
Image
Last edited by kawagumby on 04:18 pm Jul 08 2012, edited 5 times in total.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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kawagumby
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C-model flywheel repair using a later kdx flywheel

Post by kawagumby »

Here's another angle to fix the problem; instead of rotating the stator, rotate the magnets on the hub!
This certainly reinforces the conclusion that the original unmodified coils will work with the later model flywheels. :boogie:
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1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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C-model flywheel repair using a later kdx flywheel

Post by rbates9 »

So, all that is needed is a newer flywheel then turn the center hub one set of holes? or 90 Deg.? And it will work with the existing pickup?

This could save a lot of the AC bikes from the scrap yard.
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Re: C-model flywheel repair using a later kdx flywheel

Post by kawagumby »

I think it'd be easier just to rotate the stator (with the newer flywheel), ala the Fredette fix.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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C-model flywheel repair using a later kdx flywheel

Post by KDXGarage »

So, basically, cut more slots in the "C" stator and fit an "H" flywheel"??

Thanks!
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
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Re: C-model flywheel repair using a later kdx flywheel

Post by kawagumby »

I have two good original C model flywheels - one off an 86 and one off the 87. Why do some last while others don't? Both these engines are high time... and there is some rust on the flywheels...but the magnets are tight.

I came across an interesting thread in a UK site regarding the subject a while back, which linked poor removal technique as the main culprit. The upshot is that many owners don't have the right kind of puller and attempt to pry the flywheel off. That prying distorts the housing and breaks the glue bonds. That may not be the only reason for magnet failure, but it certainly could be a major contributor.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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Re: C-model flywheel repair using a later kdx flywheel

Post by davecoates »

hey Kawagumby... you wouldn't happen to still have those flywheels lying around would you? need one for '88 model
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Re: C-model flywheel repair using a later kdx flywheel

Post by kawagumby »

Sorry no, they're in engines that are being used.
Why don't you use an H model flywheel as noted in this thread?
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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Re: C-model flywheel repair using a later kdx flywheel

Post by davecoates »

Thanks Kawagumby. To be honest I don't want to spend all that money and F it up. I've managed to find some magnets from Jeff @ http://frpoffroad.com/. I just have to fit the missing magnet and have it balanced and we're good to go. :D
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C-model flywheel repair using a later kdx flywheel

Post by chrisperrera »

Cheaper than getting remanufactured parts. http://www.kdxrider.net/forums/viewtopi ... 19&t=18524

I finally made a write-up on using a Tecate 3/4 flywheel on the C series 1986 :supz:
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Re: C-model flywheel repair using a later kdx flywheel

Post by nedrowjoe »

Sorry to post bs, I'm new and need to come up with a fix for my 86 kdx200 and need quick reference to this thread.
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C-model flywheel repair using a later kdx flywheel

Post by Hail seizure »

Hi, I've just done this Mod. If you need advice just ask!
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Re: C-model flywheel repair using a later kdx flywheel

Post by nedrowjoe »

Awesome, was it as simple as using a newer flywheel and slotting the stock ignition at 90 degrees, and clocking the ignition 90 degrees?
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C-model flywheel repair using a later kdx flywheel

Post by Hail seizure »

Yes that's it.
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Re: C-model flywheel repair using a later kdx flywheel

Post by bob_jones »

nedrowjoe wrote:Awesome, was it as simple as using a newer flywheel and slotting the stock ignition at 90 degrees, and clocking the ignition 90 degrees?
http://www.kdxrider.net/forums/viewtopi ... 19&t=19867
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Re: C-model flywheel repair using a later kdx flywheel

Post by Blackflame444 »

Does anyone know how to make these posted photobucket image not blurry?
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Re: C-model flywheel repair using a later kdx flywheel

Post by kdxsully »

I think you gotta click on it. They recently started doing this to ensure they go out of business.
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Re: C-model flywheel repair using a later kdx flywheel

Post by 85' kid »

Alright, I've been going through this a little and I'm kinda confused. To start, I have a 85' KDX200, with a crispy magneto. Now if I buy a 90's KDX200 magneto, all I would need to do is move the Original 85' stator 90 degrees?
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