KDX 3 coil stator mod

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Deseret Rider
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Re: KDX flywheel inside diameter?

Post by Deseret Rider »

A most interesting approach-----I'm thinking that the four magnet rotor should work perfectly with the new plate with the two ignition coils wound in series with each other---and if the voltage output is similar----which it should be without rewinding the coils? Let us know how this comes out. Meantime, I am wondering if the magnets in the original rotor were Ok?----You said the rotor wasn't in good shape?----what was wrong with it? If rust were the only problem---had you considered using a hydrolysis method of rust removal? I've used that method to remove rust from a tank with great success? Don't know why it wouldn't have worked on the rotor if there were no other problems with it?
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Roadhazardguy
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Re: KDX flywheel inside diameter?

Post by Roadhazardguy »

Only one is the ignition coil, the other two are lighting coils just one with heaver Ga wire than the other. Only one coil went to the condenser, the other two coils just went straight out to a regulator then lights etc.. I assume. Am I missing something?

The magnets were fine on the rusty rotor, it was the inner cam on the hub that was the problem. It was pitted so bad that it was wearing down the brush on the points so I had to re adjust them every couple miles or so, I almost had no adjustment left.
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
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KDX 3 coil stator mod

Post by pumpguy »

Just wondering... the '75 G4 is a points & condenser magneto while the KDX is a CDI. Also, I am assuming the G4 is 6 volt lighting while the KDX is 12 volts. How will you incorporate the CDI ignition using this stator? Have you considered the change in voltage when you rewind the lighting coils?
Deseret Rider
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Re: KDX 3 coil stator mod

Post by Deseret Rider »

Tony----I was thinking that the single coil----the one with heavy wire---would be the lighting coil? The heavier wire to carry more current which is what would be needed for lighting. The thinner wire Coils with a lot more turns would put out more voltage----the number of turns of a coil would determine the voltage???? The reason for two such coils if they are wound in series would result in a pretty high voltage. The three magnet rotor would time the spark different than the four magnet rotor---but I think you had that figured out in that you will have to rotate the plate and drill and slot it to get the spark timing right. I'm just guessing that the CDI unit doesn't care what the timing is---it just fires the plug whenever it gets the voltage surge from the rotor--I'm thinking that the CDI was designed to work with the duel coils so that should not be a problem------and I'm thinking that the 'phase' difference that the lighting coil will see won't matter ----it simply feeds a rectifier which converts it's AC input to DC out---It doesn't care about timing? I'm pretty impressed with your plan ---and hoping to hear how it all comes out-------- (As to the 12 volt lighting output????----That's a good question? Is there a voltage regulator in the circuit that would take care of that? In the old days the Britt's used to wire in a Zener Diode whose purpose was to bleed excess input voltage to ground---thus protecting the battery from being fried.
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Deseret Rider
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Re: KDX 3 coil stator mod

Post by Deseret Rider »

Opps! I might be all wet on all of this----The old points fired stator is gone and you are feeding a CDI with a rotor which was designed to work with the CDI---right? And I may have been backwards also on the lighting could output voltage? If the new output voltage is six volts feeding 12 volt lights then it may be simpler just to change the bulbs to six volts------I am probably all confused----but still interested to hear how it all comes out.
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Roadhazardguy
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Re: KDX 3 coil stator mod

Post by Roadhazardguy »

I am by no means an electrical expert so all of this may not even work at all, so DON'T be impressed and correct me where you see fit. I hadn't even thought about the 6V thing but my plan was to rewind the lighting coils with the larger 18ga magnet wire which gives 12V in similar coils so I assume it would do the same here? Then I was going to run out to a universal 12v voltage regulator keeping it AC power not a regulator/rectifier which would convert it to DC, and from there out to a switch/lights/horn. On the ignition coil I planned on rewinding it to the stock ga wire(not sure what it is exactly yet..) then running that to the stock KDX CDI.

Should I put the two lighting coils in series? How is the KDX SR stator set up?

The G4 rotor has 6 magnets BTW.

Edit: OK so the SR lighting coils are in series.
KDXsg wrote:Thanks mike for the calculator. there is resistance shown across two point from the wound lighting coil, which I am now sure that the coil does works to a certain extent. but dont know how much output it will provide.

Btw the KDX 200 SR model have infact 2 lighting coil connected in series on the stator. Maybe I will also try to connect 2 lighting coil in series.
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
Deseret Rider
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Re: KDX 3 coil stator mod

Post by Deseret Rider »

I tend to get confused easy----but isn't it true that the rotor you are using now----and the stator that you are using now----came off a machine that had CDI ignition? If both those statements are true then it seems to me that the ignition coils would already be the proper wire size and with the correct number of turns----The old system however was wired to the ignition coil and fired when the points broke-----so can't you just add a CDI unit, placing it between the stator output and the existing ignition coil? Hmmmmm???? wonder why that would not work???? ----and it does avoid the rewinding coils problem---doesn't it? I'm just thinking out loud and throwing ideas out----maybe not all of them are GOOD ideas. Is there still a timing issue?------maybe so but I think you had that covered by putting slots in the stator plate to match the old mounting holes___and tuning it to where it runs best?
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rbates9
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KDX 3 coil stator mod

Post by rbates9 »

You shouldn't change the name of a topic.... It could confuse the simpletons. (Like me)
Roadhazardguy
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Re: KDX 3 coil stator mod

Post by Roadhazardguy »

OK so just to clear things up: I am using the stock KDX flywheel(CDI) and I'm trying to convert the G4 stator(points) to run on the KDX CDI (eliminating all the points junk from the G4 stator). I am not using the old points rotor on the KDX, the inner hub is way too small to fit on the KDX crank; I only used it for measuring the ID of the magnets. Some of the outer windings have been cut on the G4 coils (im guessing from whoever originally dissembled it) so they need to be rewound, also I'm rewinding the lighting coils to 18 GA wire to increase coil wattage so I can run bigger brighter lights. See link: http://kdxrider.net/forums/viewtopic.php?t=10226
The only issue I see with timing is the length of the G4 ignition coil is shorter(but fatter) than the KDX coil. So as the magnets pass the coil I have to figure out where the spark will occur in accordance to coil. (I assume the trailing edge of the coil?) Then I will clock the stator accordingly.
Last edited by Roadhazardguy on 10:49 pm May 20 2013, edited 3 times in total.
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
Roadhazardguy
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KDX 3 coil stator mod

Post by Roadhazardguy »

rbates9 wrote:You shouldn't change the name of a topic.... It could confuse the simpletons. (Like me)
LOL sorry about that, I thought it might but I figured this was more appropriate.
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
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KDX 3 coil stator mod

Post by pumpguy »

Would it be possible to mount the KDX ignition coil on the G4 stator plate? If yes, the ignition system wouldn't change. The only issue would be correct spark timing. I think you're on the right track with the lighting circuit.

To check spark timing, my plan is to make 2 marks on the outside of the flywheel 21 degrees apart (stock timing). Position a temporary stationary pointer so the first mark is TDC. Then, start the engine and use a strobe type timing light to see how close to the 2nd mark the spark occurs. If additional marks were made at 20 degrees and 22 degrees, you could advance or retard the ignition to see what effect that has. Also, you could see if the spark advances or retards as the RPM changes.

Has anyone done this before?
Roadhazardguy
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Re: KDX 3 coil stator mod

Post by Roadhazardguy »

Ive looked at it and I think I can make it work with the KDX coil on the G4 plate but I can't go back to the G4 coil after I mod it to fit. So I was going to save that as last resort if for some reason I cant get it to work with all the G4 coils.

That is basically what I had planned on doing with the timing, just wasn't 100% sure where to start.

I wouldn't be surprised but I don't think Ive seen any thread about it.
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
davecoates
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KDX 3 coil stator mod

Post by davecoates »

You still have that KDX 200 '88 ? Interested in selling the magneto? :P I have '88 but can't find a magneto (or magnets) ANYWHERE! :(

Also have '87 with missing magnet so desperately need either a magnet (or two for '88) or magneto for either.

Any ideas?!

Dave
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Re: KDX 3 coil stator mod

Post by jeswinehart »

PM sent to you davecoates.
Looking forward to hearing from you !

john
stephan
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Re: KDX 3 coil stator mod

Post by stephan »

HEY ROADHAZARD GUY... HOW DID IT WORK?

I HAVE AN KDX 88 AND NO FLYWHEEL... PLEASE ADVISE OF ANY OPTIONS.

THANKS STEPHAN
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