KDX Lighting Stator Rewind How-To

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Slick_Nick
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KDX Lighting Stator Rewind How-To

Post by Slick_Nick »

Quick How-To on rewinding your stock lighting stator. The setup I ended up with tested out at 98W, the stock stator at 60W. Now, I don't dual-sport my bike, but I wanted a brighter headlight for those nights when you're caught out just after sunset. 100W is more than enough for a standard headlight / tail light. This procedure was done on an A/H series KDX, but the basic procedure should apply for any bike with a single coil AC generator. Onto the rewind.

You will need:

- A flywheel puller
- A flywheel holder
- Socket set
- Soldering iron
- Side cutters / wire strippers
- 17GA coated magnet wire, 1 small spool should do

Remove the flywheel cover, use a flywheel holder to remove the 17mm nut on the flywheel. use your puller to remove the flywheel. Remember, on the KDX those are LEFT HAND THREADS for the puller.

Image

Unplug the stator wire. The connection is found up on the right side of the bike just by the shock reservoir.

Remove the three phillips screws with an impact hammer if they're stuck, and remove the stator. Pay close attention to the timing reference marks, so you can put the stator back in correctly.

There are two coils on the stator plate, the ignition coil, and the lighting coil. The lighting coil (the one we're concerned with) is the larger, uncoated coil. Go ahead and remove the coil from the stator plate, by removing the two phillips screws. You will need to clip the power wire, do so as close to the coil as you can. This will leave lots to solder back on later. You should now have the coil all by itself.

Image

Image

Now, de-solder the ends of the coil wires, the black ground wire can remain. You want to clean all the old solder off. Remove the old coil of wire. There will be a LOT of it, like 200 yards worth, not kidding.

Pay special attention to how the wire is wrapped around! What direction, and where it starts and where it ends.

Using your coated wire, simply rewind the stator just like it was stock, leaving extra at each end for soldering. Read:

For the best possible result, keep the wire as tight as possible. I had a friend hold the spool taught while I wrapped the stator. This is a time consuming process, be patient and it will pay off. The more wraps of wire you can fit the better, and the tighter they're packed the better.

Be really careful not to scratch the coating off the wire. If there's a short in the stator, you've just dropped your output to nothing. The idea is to fit as much wire as possible on the coil, obviously without hitting the flywheel. The stock wire was wound about to that point, you can use my pics for reference, but that is about all that would fit under the flywheel.

Done wrapping now? Good. Time to solder those ends on. I cut just enough to reach the soldering terminals. This is definitly a measure twice, cut once kinda deal.

Scrape the coating off the last 1/4" or so, and solder the wire to the posts. This was easily done because you paid attention to how it all came off, right? :thumbsup:

Solder on a new output wire where the old one was attached, leaving about 3" to work with. Your finished stator should look like this:

Image

Image

Cut the output wire to length, solder it back to the output wire you cut in the harness, and heat shrink wrap it to seal it in.

Bolt the coil back to the stator plate:

Image

I like to check the coil for continuity at this point, right from one end of the coil wire to the end of the harness yellow wire. Would be a shame if there was a short and you waited until it was back together to find it, wouldn't it? Any good multimeter is capable of checking continuity.

Reinstall the stator plate, paying attention to the timing marks. This would be a good time to advance or retard your timing, depending on your riding preference. Refer to your service manual for details on that.

Image[/IMG]

Reinstall the flywheel, make sure it doesnt contact your coil! Bolt the flywheel cover back on, and fire it up!

I tested my bike right at the headlight socket, with the stock headlight and tail light on, no other electrical equipment installed.

Image

12.53v AC @ 7.90a AC gives 98.987 watts. Measurements taken just above idle.

Idle gave 12.34v AC @ 7.81a AC, which works out to 96.375 watts.

Image

Image

VIDEO:

So, just under 100W for about $18 and a bit of spare time. Good luck!
'00 KDX 220R
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Post by SS109 »

Excellent write up. Kudos to you! :prayer:
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Post by Julien D »

Good job on the how-to, Nick.

When someone can, this should be a sticky.
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Post by SS109 »

>|<>QBB<
juliend wrote:When someone can, this should be a sticky.
I agree. The topic of upgrading the stator comes up often and this would cover it.
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Post by TWMOODY »

Nick
Your set up with the DVOM shows a 7.9a reading and you claim you
are running all stock bulbs.
The stock bulbs would draw about 3.2 amps.
Can you explain what is drawing the other 4.7 amps your meter shows???
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Post by Slick_Nick »

Thanks guys.

Wanted to add, that I might try taking a reading directly from the stator itself. The voltage is corrected by the regulator (duh!) to always remain around 12.3vAC or so. The current available will increase with the bigger stator, but voltage won't increase. On the stock stator, voltage was quite a bit lower at idle, like around 10.9-11.2v. Now, measuring before the regulator really is pointless, in the sense that the regulator will never let the electrical system "see" more than 12.5v, lest you start popping bulbs and stuff. More just for kicks, see what kinda voltage is literally coming from the stator itself. Mind you, wouldn't really matter as anything before the regulator wouldnt be used for anything.
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Post by TWMOODY »

>|<>QBB<
Slick_Nick wrote:>|<>QBB<
TWMOODY wrote:Can you explain what is drawing the other 4.7 amps your meter shows???
No I can't. Rear lightbulb is a 10W, and the headlight is 25W bulb. Should put their current draw closer to 2.9A.

Unless I've got a 65W bulb hidden somewhere I don't know about? :mrgreen:
That's the reason I'm asking.
Without a 7.9amp load you can't have a 7.9amp output.
How did you have your DVOM hooked up ?

The actual draw on the stock bulbs would be just under 2.8amps at
12.53volts.
My bad on that I was thinking 40watts total on fnt and rear bulbs
Last edited by TWMOODY on 01:06 am Feb 20 2011, edited 1 time in total.
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Post by Slick_Nick »

>|<>QBB<
TWMOODY wrote:>|<>QBB<
Slick_Nick wrote:>|<>QBB<
TWMOODY wrote:Can you explain what is drawing the other 4.7 amps your meter shows???
No I can't. Rear lightbulb is a 10W, and the headlight is 25W bulb. Should put their current draw closer to 2.9A.

Unless I've got a 65W bulb hidden somewhere I don't know about? :mrgreen:
That's the reason I'm asking.
Without a 7.9amp load you can't have a 7.9amp output.
How did you have your DVOM hooked up ?
You can see in the video how it's hooked up. Double checked my DMM manual, it was hooked up right.
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Post by TWMOODY »

>|<>QBB<
Slick_Nick wrote:>|<>QBB<
TWMOODY wrote:>|<>QBB<
Slick_Nick wrote:>|<>QBB<

No I can't. Rear lightbulb is a 10W, and the headlight is 25W bulb. Should put their current draw closer to 2.9A.

Unless I've got a 65W bulb hidden somewhere I don't know about? :mrgreen:
That's the reason I'm asking.
Without a 7.9amp load you can't have a 7.9amp output.
How did you have your DVOM hooked up ?
You can see in the video how it's hooked up. Double checked my DMM manual, it was hooked up right.
Nope
Can't see the hook up while your measuring amperage however it should be hooked up in series with the headlight to properly test amperage.

Didn't watch the video just looking at your pics.
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Post by Slick_Nick »

Black wire hooked to the COM port, red wire hooked to the 10A max input, and you can see the multimeter setting was on AC amps. Hooked the red wire into the red side of the headlight harness, and the black into the black side as per the pics.
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Post by Slick_Nick »

What I could have done is unplug one of the headlight wires and run the DMM in series to it, but that would only give me current draw for the headlight, nothing else.
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Post by TWMOODY »

The only way to measure true output is to have the actual load
you want to measure installed in the system then install your DVOM
in series somewhere (doesn't matter where) within that system.

Not knocking the work you have done because it truly looks
fantastic BUT the output you claim is a BOGUS number the way
you are testing.
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Post by Slick_Nick »

Not quite.

Look at the KDX wiring diagram:

Image

The way I had that hooked up, when the switch was turned on, it was shorting the output wire from the stator directly to ground. I'm no electrical engineer, but from what I remember in grade school science, when things are shorted out, they tend to draw maximum current through them.

Correct me if I'm wrong?
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Post by TWMOODY »

That is not correct Nick.
Here is your schematic with the points indicated for hook up to properly check for output ( amperage )

There are also a couple other areas that the same test could be done so
but this will point out the " How To "

You would add more load (bulbs of known wattage) to the headlight circuit
and keep adding until you voltage was no less than 12volts telling you your
max output at 12V.

[img]:720:562]http://a6.sphotos.ak.fbcdn.net/hphotos- ... 8140_n.jpg[/img]
Last edited by TWMOODY on 09:03 pm Feb 20 2011, edited 2 times in total.
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Post by Slick_Nick »

Right, I understand that, but when I had it hooked up previously, when the DMM was connected, having the stator shorted directly to ground, gave me 7.9a. Would it not make sense that this is the maximum the stator would output? I've got a few H7 headlight bulbs, I'll just wire those instead of the headlight (I think I even have a 100W H7 lying around) so that I don't end up with a daisy chain of dinky bulbs everywhere.

Doesn't look like it's fused anywhere, but is the stock wiring ok for 100W through the headlight? Would only be for a minute or so.
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Post by Slick_Nick »

I'll just grab right off the yellow stator wire, prior to the switch, just because it's easier. I'll have a second voltmeter (analog unfortunately) hooked up directly to the headlight socket to watch voltage at the same time.
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Post by TWMOODY »

>|<>QBB<
Slick_Nick wrote:Not quite.

Look at the KDX wiring diagram:



The way I had that hooked up, when the switch was turned on, it was shorting the output wire from the stator directly to ground. I'm no electrical engineer, but from what I remember in grade school science, when things are shorted out, they tend to draw maximum current through them.

Correct me if I'm wrong?
On the last statement if things are shorted they tend to draw max current
that is true, BUT you haven't shorted to ground AND measured voltage at the same time.

What you have done is used your meter to short out the system showing
a 7.9 amp draw but at what voltage ??
More than likely 7.9amps at 2 or 3 volts.
Pretty much useless test not knowing the voltage.
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Post by TWMOODY »

Your good with that 100 watt bulb for testing and I would guess
your voltage falls well under 12 volts
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Post by Slick_Nick »

So, i guess I can try two things. Short it to ground again, and measure voltage simultainously, or try the test as you mentioned. I'll give both a go, and see what I come up with. With the voltage regulator in the system, does it not keep the voltage at or near 12V anyway? I know excess is shunted to ground, but wouldn't amperage then be limited as the VR is trying to maintain 12v?
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Post by TWMOODY »

>|<>QBB<
Slick_Nick wrote:I'll just grab right off the yellow stator wire, prior to the switch, just because it's easier. I'll have a second voltmeter (analog unfortunately) hooked up directly to the headlight socket to watch voltage at the same time.
As long as you add your DVOM in series on that yellow wire that's a good
test too.
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