CDI and coil interchangability?

Discussion specific to the various air-cooled KDX models sold in the USA
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

From stock position rotated counter-clockwise approx 90 degrees. The timing mark at TDC zero degrees is roughly matched to the timing mark on the case.
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

If you did it right, it could only be at 0 or 180. Otherwise you'd be in the original slots at 90 or 270. Referencing the the little triangle sticking out from the case at approximately your 10 or 11 o'clock on the case
Hail seizure
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CDI and coil interchangability?

Post by Hail seizure »

Hi here is a pic of my stator as it is now.
Image
So I have to go anti clockwise a bit more?
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

That looks 180degrees wrong. Exactly backwards. The coil that's on the left, should be on the right. The pic that I posted is almost the same orientation as it would be in the bike. Go back and look at my pic again. Source coil on left, lighting coil on right. Unless something about your bike is different than mine. I take no responsibility.
Hail seizure
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CDI and coil interchangability?

Post by Hail seizure »

Yes got it, I will try it 180 about, thanks.
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

The black wire would run about 1/4th the way around (clockwise) to exit the case unless you really configure the holder. If anybody can explain better, feel free to jump in.
Hail seizure
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CDI and coil interchangability?

Post by Hail seizure »

She lives! Re installed the stator 180 about and it's now running! Next question how do I set the timing correctly?
Here are some pics of the stator current position and the flywheel at TDC.
Image
Image
Image
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

I had to do trial and error on the timing. Ride, adjust, repeat. When it got the way I wanted, I made a mark and went on about my business. Others might have better input on that. The way you have it now is as far retarded as it will go unless you lengthen the slot. My uneducated guess is that it might currently be too retarded... my uneducated guess lol
Hail seizure
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CDI and coil interchangability?

Post by Hail seizure »

OK will give it a go. Thanks.
Hail seizure
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CDI and coil interchangability?

Post by Hail seizure »

Just an update, bike is running fine now. Had to adjust the timing slightly but it now starts 1st kick and runs well.
I also fitted a 15T front sprocket and now estimate the bike hits about 60mph flat out.
Even got the headlight working! Thanks for the advice.
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Re: CDI and coil interchangability?

Post by bob_jones »

Outstanding sir. Glad to hear it worked. You don't know it, but you helped me with my rear disc brake conversion as well! :supz:
Hail seizure
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Re: CDI and coil interchangability?

Post by Hail seizure »

Excellent, any pics? What caliper etc did you use?
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Jaguar
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Re: CDI and coil interchangability?

Post by Jaguar »

too far clockwise and the engine is better at low RPM but worse at high RPM.
find the position that is OK for power at all RPM
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

Hail seizure wrote:Excellent, any pics? What caliper etc did you use?
C axle.
E wheel, spacer, shim, disc, caliper, caliper holder, lines, master cylinder, and reservoir.
H pedal

Had to grind the carrier locator on the swingarm to fit the slot on the caliper holder.
Wheel was too far left.
Sprocket was too far right.
H spacer and shim on left side. Big fender washer on right side.
Had to put washers between sprocket and hub to locate sprocket properly.
Wheel still a smidge too far left but not bad.
Probably still need to dial in a bit better.
If I had it to do again, I'd have used caliper holder off of either and 86-ish kx or some early 2000's ninja. Might not have ahd to grind the swingarm piece at all.
Had to get some hex bolts for caliper-to-holder because the allens hit the swingarm too much.

Had to weld a bolting location to fram for bracket I made for master cyl.

It wasn't a terrible PITA but there was some modding to it.

I'll see it I can find some pics.
Hail seizure
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CDI and coil interchangability?

Post by Hail seizure »

Wow! Some work gone into that!
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

Hey scratch that. I thought I had kdx rear wheel until I went to replace bearings. Now it's clear that this is not a kdx wheel. All the other parts are kdx but not the wheel and spacers. Its most likely a CR wheel. Will update when I know more.
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Re: CDI and coil interchangability?

Post by bob_jones »

Update: Have figured out that my rear wheel is a 1987 - 1988 Honda CR125/250/500 FWIW. Bearings are done. All is well.
arjay200
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Re: CDI and coil interchangability?

Post by arjay200 »

bob_jones wrote: 01:44 pm Sep 18 2016 I rotated the stator by cutting new slots and installed an H series rotor
Hey Bob, I'm trying the same thing out on my '87 motor.

H Series staor coil, flywheel and CDI (and 2004 CR250 secondary coil).

Did you use an H Series source coil, or did you stick with the '88 coil? I couldn't tell from your photo.

I have a new H coil lying around, but the holes are slightly too narrow, so would need to slot it.

Cheers for any info. Hope you still have the KDX!
arjay200
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Re: CDI and coil interchangability?

Post by arjay200 »

Hail seizure wrote: 02:57 pm Oct 13 2016 Hi here is a pic of my stator as it is now.
Image
So I have to go anti clockwise a bit more?
Hi could you post that pic again? Thank you
bob_jones
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Re: CDI and coil interchangability?

Post by bob_jones »

arjay200 wrote: 05:08 am Jan 02 2020
bob_jones wrote: 01:44 pm Sep 18 2016 I rotated the stator by cutting new slots and installed an H series rotor
Hey Bob, I'm trying the same thing out on my '87 motor.

H Series staor coil, flywheel and CDI (and 2004 CR250 secondary coil).

Did you use an H Series source coil, or did you stick with the '88 coil? I couldn't tell from your photo.

I have a new H coil lying around, but the holes are slightly too narrow, so would need to slot it.

Cheers for any info. Hope you still have the KDX!
Hi arjay. I used the c-series stator. Actually I've replaced with a rickystator high output stator for c-series. But the only h series part I used was the flywheel. [image]
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