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hey guys this is my first post here, i just picked up 2 1985 kdx 200s that had been sitting pretty much outside for 8 years. so far i rebuilt the top end and carb in one of them, it started, ran perfect but had a float bowl leak, so i fixed that, got it all put together and no spark. the other bike had perfect spark so i put the coil from it on the bike i rebuilt and still no spark, what else could it be? I've seen people post saying it could be the stator but id hate to have to do all the work to get to it if you think it could be something simple, since it ran perfect for 5 minutes then nothing. any help would be greatly appreciated!

Thanks for reading
-john Ayers proud owner of 2 85 kdx's

Check the simple stuff first. I would check the kill switch first, and then go from there.

I agree. Faulty kill switches cause this problem a lot. Disconnect the kill switch wiring and see if it has spark. Just remember that if you start the bike like this you won't be able to shut it down easily. If that doesn't work I'd check the bike's wiring for shorts to ground or broken wires/bad connections. The kill switch just shorts the ignition to ground to shut off the spark. If the wrong wire is rubbing against the frame you'll get the same effect.

ok today i went threw the whole bike, checked every ground and every wire. I also took apart the kill switch to eliminate that. using a multi meter i tested to see if it was getting power to the coil, and it is getting about 14 volts per kick to the coil. is that enough? the coil works perfect on the other bike so i dont think that could be the problem. what should i do next?

ok i rebuilt the other bike too and now it has no spark also haha, so i think i might have messed up the coil by taking it off and on 10x, so im going to get a new coil and go from there

85kdx200dippin wrote:ok i rebuilt the other bike too and now it has no spark also haha, so i think i might have messed up the coil by taking it off and on 10x, so im going to get a new coil and go from there

pull the stator cover and check that it isn't full of water?

continuity between coils and cdi ?

Yes, take the ignition covers off and check in there.

Congrats on the two '85's.

i pulled the side of the motor off seems dry, do i need a special tool to get in there further? I suck with electrical stuff how do i check for continuity between the coil and cdi? I really appreciate the help guys, It's allot different working on my own bikes then it was working on them with my dad hah.

the ground path from the base of the spark plug to the stator coil and CDI is thru the engine metal and the screws holding down the stator coil and adjustment plate. So corrosion there will mess up the ignition system. That ground path is essential. Take off the flywheel, take everything apart, and clean off all corrosion.

i got the nut off the flywheel, is there any tricks for getting the flywheel out without a puller? or do i have to go buy one

You'll need a puller.

As I recall, that era of bike had issues with flywheel magnets coming loose. There were a number of ways of fixing this, you may need to search ancient history.

Kind of funny that both had spark until you worked on them, Eh? I go through that a lot, and I'm an Engineer. It is surprising any of my crap works at all.

yeah still no progress, got flywheel off everything looked fine i cleaned it all up, it is getting 16 volts from the cdi to the coil, all grounds are good, i dont see why it wouldnt spark, just put a brand new coil on it too, thinking of maybe tearing into all the wires next and following them to makesure they arnt messed up, allot more work then i expected to do haha.

I'm pretty sure the minimum AC voltage you want from the stator coil when kicking the bike over is 30 volts with the CDI disconnected

ok i put the bikes away for winter, now im back to fixing them.

now i have spark, i have gas, and cant get it to fire, im thinking its probably a carb issue, so next step is going to be rebuilding or possibly buying a new carb. wife is putting pressure on me to get rid of them so i need to get them running asap to change her mind.

is there a cheap place to order a new or rebuilt carb? or should i rebuild it myself? thanks guys

Two other requirements for the engine to run are compression and correct spark timing. Do you know what these are?

Will it at least fire if you squirt a little ether down the spark plug hole? Don't go crazy with the ether since it's got no oil in it. A squirt or 2 shouldn't hurt. I sometimes need to do this to get the leaf blower etc. going after sitting for a season or 2.