Checking Stator & Fly Wheel

Discussion specific to the various air-cooled KDX models sold in the USA
Boltonbubba
Member
Posts: 23
Joined: 12:24 pm Jul 09 2020
Country: America

Re: Checking Stator & Fly Wheel

Post by Boltonbubba »

Removing the magnets was challenging. Used a dremel to grind away excess JB Weld along 3 edges. After this was complete i took a small hammer and rapped the side of the flywheel lightly to get the remaining bond to break. It’s important to be gentle and not rap too hard as you risk shattering the magnet. 3 of 4 popped off cleanly, the 4th left a small piece. Take note all epoxy must be cleanly removed as there are two stops inside the flywheel that allow you to position it vertically and horizontally in the correct position.
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Boltonbubba
Member
Posts: 23
Joined: 12:24 pm Jul 09 2020
Country: America

Re: Checking Stator & Fly Wheel

Post by Boltonbubba »

Reference the pictures to see the magnets position stops on the inside of the flywheel. Note the magnets should alternate N-S-N-S. There are 3 vertical lines on the outside edge (I didn't show that picture) of the flywheel, on the opposite side goes the 1st magnet in the N position.
mcshaw16
Member
Posts: 6
Joined: 08:47 pm Feb 02 2025
Country: United States

Re: Checking Stator & Fly Wheel

Post by mcshaw16 »

Boltonbubba wrote: 08:51 pm Jan 27 2022 Gents, after much trouble shooting I think I finally figured out the problem. When the previous flywheel owner refluxed the magnets he glued them on in the wrong order NNSS. The magnets are supposed to be NSNS. Also there are stops on the flywheel to help you position the magnets correctly. Soooo all you have to do is mix up some JB Weld (I use marine grade) coat the back of the magnet and the top/sides and slide it into position. Of course you need to clean off rust and old epoxy before regluing. But pretty easy. To detect what pole the magnet is you can buy a simple magnet pole detector (another NS magnet on a swivel…pivots to tell you the magnet pole) off Amazon for $6. Super easy to test…you’ll have you answer in less than a minute.
Hi - I picked up a non running 1988 kdx200 this winter with the same issue. Bought under the assumption that it had no spark “due to a bad cdi”….from seller. After doing a lot of troubleshooting with a multimeter I ended up replacing the cdi with a known good one and new source coil from Ricky Stator, I still had no spark. After seeing this post I checked the flywheel magnets with a polarity tester and the were indeed in the wrong order, NNSS. I re-expoxied with JB Weld and finally had a great spark! Problem is, the timing is way off, kicking back real hard, almost like it’s trying to fire backwards. I’ve rechecked magnet positioning and they are in the correct spots using the alignment tabs. I understand the after market source coils put out more voltage which advances the timing quite a bit. I have tried retarding the timing in a variety of different settings and get the same result. When I reset the magnets, I did so with North at the keyway. I have seen conflicting info on whether or not it matters if you start with North or South at the keyway and I am wondering if this is my issue. Based on what I see here I think I have it correct, but I just can’t understand why the timing is so off. I’m kind of stuck at this point and I don’t know what else to try. Any help would be appreciated.
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