1987 Kawasaki KDX200 timing?? Please help

Jay Dawg · Post by **Jay Dawg** » 12:24 pm Apr 24 2015

Hello, New member here, Jay. I recently bought a pristine 1987 KDX200. I had some issues with it revving high and thought it needed new crank seals. I had read online that you do not need to split the case to replace these. I bought a threaded flywheel puller from RMStator (website stated it would work with my model) and it did not work. The KDX flywheel is not threaded for the easy off flywheel tool. I ended up damaging the ignition coil getting the flywheel off. (the case has to be split on the 1987 KDX to replace the crank seals anyway- at least the ignition side) Anyway, I order a new ignition coil from RMstator for $29 and put it on. When I fire up the bike, it runs backwards. The timing marks on the stator plate are lined up with the mark on the case. I then reversed the wires on the coil and it is still running backwards. My guess is the timing is off 180 degrees??

I am assuming this is a timing issue. The flywheel (rotor) has 3 marks on the side and the case has an arrow embossed in it, but I am not sure how to set these.

Any advice or help is much appreciated. Jay

Jaguar · Post by **Jaguar** » 02:43 pm Apr 24 2015

the new coil has more "turns" than the original coil which produces more voltage which causes the ignition to happen earlier which causes the piston to reverse direction and make the engine run backwards.
rotate the stator plate as far counter-clockwise as it will go.
that might make the thing rideable but still you should find an original stator coil to put on to give the bike the right timing.

KDXohio · Post by **KDXohio** » 05:28 pm Apr 24 2015

Sounds fun to ride!

Post by **bufftester** » 05:57 pm Apr 24 2015

Jaguar wrote:the new coil has more "turns" than the original coil which produces more voltage which causes the ignition to happen earlier which causes the piston to reverse direction and make the engine run backwards.
rotate the stator plate as far counter-clockwise as it will go.
that might make the thing rideable but still you should find an original stator coil to put on to give the bike the right timing.

???
More voltage out of the stator coil will NOT make your bike run backwards. The ignition timing is dependent on the timing of the pulse from the stator, not on the voltage of the pulse. If I remember correctly the 87 stator plate has only two bolts holding it on, so it is possible to put it on upside down so that the lighting coil and the ignition coil are swapped which would make you run backwards. Reference your service manual to make sure you have it installed correctly, and that the flywheel is properly indexed and the woodruff key is installed (without it your flywheel can rotate on the crank which could also make you run backwards)

KDXohio · Post by **KDXohio** » 07:49 pm Apr 24 2015

bufftester wrote:
Jaguar wrote:the new coil has more "turns" than the original coil which produces more voltage which causes the ignition to happen earlier which causes the piston to reverse direction and make the engine run backwards.
rotate the stator plate as far counter-clockwise as it will go.
that might make the thing rideable but still you should find an original stator coil to put on to give the bike the right timing.
???
More voltage out of the stator coil will NOT make your bike run backwards. The ignition timing is dependent on the timing of the pulse from the stator, not on the voltage of the pulse. If I remember correctly the 87 stator plate has only two bolts holding it on, so it is possible to put it on upside down so that the lighting coil and the ignition coil are swapped which would make you run backwards. Reference your service manual to make sure you have it installed correctly, and that the flywheel is properly indexed and the woodruff key is installed (without it your flywheel can rotate on the crank which could also make you run backwards)

+1 I hadn't even read the other response. More windings would definitely not change the timing of the discharge.

kawagumby · Post by **kawagumby** » 01:33 pm Apr 25 2015

The timing doesn't have to be off much to cause the engine to run backwards. A properly timed bike will run backwards in certain situations, like using engine braking while sliding backwards down a steep trail LOL...

As said by Bufftester, check out everything including the key - also check the flywheel magnet locations...one may have come loose and is in the wrong position (they come loose frequently on these bikes).

Jaguar · Post by **Jaguar** » 01:48 pm Apr 25 2015

Buff, I happen to be an electronics technician and have a lot of experience with KDX ignition systems.
When a CDI uses only the voltage from the stator coil, without a separate pickup coil, then the voltage definitely does alter the timing because the timing is voltage dependant. When the negative voltage reaches a certain level then the circuit is triggered to dump the positive voltage it has stored into the high voltage coil to produce a spark. When the stator coil is rewound with more turns that before (usually due to using a thinner wire) then it produces more voltage which causes the spark to happen earlier.
Too early a spark and the piston will reverse direction.
Please click on my signature link if you want to learn more about the KDX CDI and the ignition timing.

KDXohio · Post by **KDXohio** » 02:39 pm Apr 25 2015

Jaguar wrote:Buff, I happen to be an electronics technician and have a lot of experience with KDX ignition systems.
When a CDI uses only the voltage from the stator coil, without a separate pickup coil, then the voltage definitely does alter the timing because the timing is voltage dependant. When the negative voltage reaches a certain level then the circuit is triggered to dump the positive voltage it has stored into the high voltage coil to produce a spark. When the stator coil is rewound with more turns that before (usually due to using a thinner wire) then it produces more voltage which causes the spark to happen earlier.
Too early a spark and the piston will reverse direction.
Please click on my signature link if you want to learn more about the KDX CDI and the ignition timing.

I have not had my flywheel off but from other posts and pictures I was under the impression we had a separate pickup coil...Do we not?

Post by **bufftester** » 05:06 pm Apr 25 2015

And I happen to be an Electrical Engineer with almost 30 years in the fields of electronic warfare/countermeasures and high power microwave radar design, but that doesn't alter the basic electronic theory behind a CDI.

OP, on the 1987 KDX, there is a separate charging coil and a separate pickup coil, and they ride piggyback on the stator plate. Each of them has two wires. Ensure that the wires are connected to the proper locations on the harness and that they are physically in the correct orientation. The thicker coil should be closest to the plate with the thinner coil riding above it on standoffs. As Kawagumby said, these older models have a tendency for the magnets to come loose so check that as well, and make sure you reinserted the woodruff key on the crankshaft when you reinstalled the flywheel. Let us know how it goes.

As for the soapbox:
The flywheel with its attached magnets charges a high voltage capacitor, which is then fired through the use of an SCR. That much we agree on. The timing of that discharge is NOT dependent on the voltage on the charging circuit, but wholly on the rotation of the crank. Whatever voltage is on the charge capacitor at the time it is discharged is passed through the primary of the ignition coil. So any change in voltage on the charging circuit of the CDI does directly impact the output voltage of the coil to the plug, but again, the voltage level is not the determining factor in the timing of the discharge. What you are describing where the timing is voltage dependent is typical of IDI systems that are popular in cars, but not used in our particular application.

Jay Dawg · Post by **Jay Dawg** » 07:26 pm Apr 25 2015

Thanks for all the replies so far. I still have not got this thing figured out, but I will keep this thread posted as things progress as it may help others in the future. I spoke with a technician at RMStator and he thinks the polarity may be reversed on the coil they sent. He wants me to send the coil back along with my original coil so they can see how the original was wound and what size wire. The magnets and woodruff key are both in perfect shape. My stator has a single ignition coil on top and a lighting coil on the bottom. RMStator sent a wide coil and a thin coil, but I only used the wide one because they both would not fit under flywheel. Thanks again for all the info. Here is a picture of the KDX (almost mint condition!!) Jay

Jaguar · Post by **Jaguar** » 10:01 pm Apr 25 2015

nice looking Kawi.
On my 1989 KDX200 the CDI depended only on the stator coil voltage. I´m unfamiliar with the 87 model.
If it does have a separate pickup coil then the stator coil voltage is not an issue.

Post by **bufftester** » 03:17 pm Apr 26 2015

There is one wide coil (lighting) and two thinner ones for ignition, and you have to run both of them. If your original didn't look like that then it is possible that some one changed plates. Any pics would help. The stock 87 stator plate should look like this:

Jay Dawg · Post by **Jay Dawg** » 08:45 pm Apr 27 2015

I sent the ignition coil back to RMStator today along with my original coil. The technician there seems to think the polarity is reversed. The picture posted of the 1997 coil set up does not look like mine. The 1987 only has 1 wide ignition coil instead of 2 thin ones. I'll follow up after they send me the coil back and see how things turn out. Thanks, Jay

Post by **bufftester** » 08:10 pm Apr 28 2015

The pic above IS for the 1987 KDX 200. The later bikes had a single ignition coil and single lighting coil on the stator plate. Some pics of the flywheel, stator plate would help.

Jaguar · Post by **Jaguar** » 12:52 am Apr 29 2015

if it is wired backwards then it will cause the ignition to be very advanced. But what I previously said also holds true, if it isnt backwards then it is putting out more voltage than stock and causing ignition advance.
Maybe your bike is later than 1987.

Jay Dawg · Post by **Jay Dawg** » 10:20 am May 22 2015

Hey, It has been several weeks I have been waiting to get the coil back from RMStator. It arrived yesterday and I soldered it in and no fire!! I checked the coil they rewound and it ohms out at 262 ohms. I tested the wiring all the way to the CDI and have 262 ohms going into the CDI. I am getting zero spark. The bike is a 1987 and maybe someone along the way changed the ignition. It only has 1 ignition coil and 1 lighting coil. RMStator rewound the original coil. All the magnets are perfectly in place and the key is not damaged.

Any advice or info much appreciated. I hate to part out this bike because it is in perfect shape and ran well (see wheelie pics above

) prior to having this ignition problem. Please help- I am stumped.

Jay

Jaguar · Post by **Jaguar** » 05:58 pm May 22 2015

http://www.dragonfly75.com/moto/fixing-ignition.html

Jay Dawg · Post by **Jay Dawg** » 09:31 am May 23 2015

Thanks for the link Jaguar!! Here is where I am now. I printed the troubleshooting guide and went step by step just now on the bike. I am getting 262 ohms and 38 volts AC going into the CDI (this tells me the ignition stator coil is good). If I hold the 2 wires coming from the CDI to the spark plug coil, I get nothing. This leads me to believe my CDI is bad. Maybe during the whole "running backwards" debacle, the CDI was shorted out??

Any other ways to test the CDI before I drop the cash on a new one?? Thanks again for the help. Jay

KDXMainer · Post by **KDXMainer** » 07:16 pm Oct 08 2016

Still waiting to hear thee outcome?

Jaguar · Post by **Jaguar** » 04:36 pm Oct 10 2016

disconnect the CDI from the high voltage coil and hold the CDI bare wires in your hand, not shorting out but both wires touching your skin.
Then turn the engine over, gradually faster, and see if you feel any spikes of voltage. That voltage spike is around 100 volts at idle so you should be able to feel it. If not then suspect the CDI. But you should replace the hv coil also because it may be the reason the CDI went bad and you don't want the same happening to a new CDI.

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