KX Riders
Maintenance & Technical => KX250 / KX125 => Topic started by: NLburden on May 31, 2016, 08:03:03 AM
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Hi guys, Im trying to fix my brothers dirtbike for him and could use some guidance. It is a 01 kx 250 two stroke. Its been to two different garages and has had the engine completely rebuilt top and bottom end. The problem is the bike isn't producing any spark. Last time he was riding the bike. the bike was dying down and trying to shut off. Now a days it doesn't start and there is no spark. Other then changing out the spark plug, what are some common tactics for troubleshooting this?
Also can someone explain how the electrical system on these bikes work? What components are into play, and what discharges the spark? Thanks!
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try disconnecting the kill switch 1st...to rule out if it's faulty or not...
if that makes no difference, go over all the connections real good, look for any blue-ish/green corrosion in the plugs, be sure there's no exposed wires, or broken wires...get a little dielectric grease in the plug connections...
check your spark plug cap closely for a hairline crack...
make sure everything is grounded good...no rust or paint under any grounds...
hopefully one of those things will cure it...if not, then it's off to testing components.
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pull the mag cover too, and be sure everything in there is also in order.
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Okay perfect thanks alot, ill start with what you've mentioned and go from there!
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try disconnecting the kill switch 1st...to rule out if it's faulty or not...
if that makes no difference, go over all the connections real good, look for any blue-ish/green corrosion in the plugs, be sure there's no exposed wires, or broken wires...get a little dielectric grease in the plug connections...
check your spark plug cap closely for a hairline crack...
make sure everything is grounded good...no rust or paint under any grounds...
hopefully one of those things will cure it...if not, then it's off to testing components.
Poked at the bike again earlier.
1) Disconnected the killswitch, still didn't get any spark. I only see two wires coming from the kill switch, I assume one goes to ground? I put it back the way I found it. Also continuity checked the killswitch, seems to be working.
2)Went over the connections, cleaned up some rust I found on a ground which looks like a solenoid directly behind the forks. I examined the spark plug wire and didn't see anything majorly wrong either
3)I removed all the grounds I could find to verify that they aren't corroded. I cleaned up a few and reassembled.
I would like to check the magneto , coil, etc. How do I proceed with checking these things and what do I have to remove? I know I do not have very much experience with two strokes, but from reading online I think the CDI helps regulate voltage, the stator would create the spark, however I am still a bit unsure of what is going on electrically exactly.
Thank you highly for the input. Hopefully I'll have this thing running again
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If you have a OHM meter here is the specs for your stator
While to Red 7-15 Ohms
Yellow/While to Yellow 1-5 Ohms
It would also do you good to buy a Clymer or similar service manual.
Do not buy a owners manual..
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Hey Blaster I believe it was you that wrote up a killer thing on the electrical but maybe it was just for the K5. But it sure helped me get my issues straighten out.
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Yes, it was specific to the K5 but the principals are the same.
The only difference is the ohm specs and wire colors, and wire amounts :-)
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If you have a OHM meter here is the specs for your stator
While to Red 7-15 Ohms
Yellow/While to Yellow 1-5 Ohms
It would also do you good to buy a Clymer or similar service manual.
Do not buy a owners manual..
Yes, I do have a good fluke meter, however it is a multimeter and not a analog ohm meter. Yes a service manual would be great, I normally work on offroad trucks and find the manuals are usually free online. I'll look locally for a clymer. I will let you know the readings once I get a chance, thanks!!
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If you have a OHM meter here is the specs for your stator
While to Red 7-15 Ohms
Yellow/While to Yellow 1-5 Ohms
It would also do you good to buy a Clymer or similar service manual.
Do not buy a owners manual..
Picked up a spare set of parts from another bike that was supposively running before it was scrapped. Anyways I did some checks earlier. Do i have to remove the stator in order to do these checks or just conduct the checks from the connector with the stator still in place? I did the checks on my spare stator that i bought it turned out good. like 13 ohms and 3 ohms. I tried to check the stator that is installed in the bike and couldn't get any resistance from the pins in the connector. Wasn't getting any resistance at all.
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Bump
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bump
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So, did you swap out your good stator with the bad one?
If so, what happened?
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Swapped out stators today on the bike with another one. No spark still. I also used a test light on the connector while cranking the engine over to see if any voltage was being created from the stator. Still no spark. any suggestions?
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hmmm...could be the ignitor...which is the black box under the seat inside the air-box.
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Also changed out the igniter ( black box connector under the seat ) with a spare one however no spark either
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how about the regulator behind the forks on the frame neck...have you swapped that yet?
or have you tried swapping the coil too?
another thing, that's rare, but not uncommon...is the magneto goes bad....you can try swapping that too if you have access to a spare.
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If you have a OHM meter here is the specs for your stator
While to Red 7-15 Ohms
Yellow/While to Yellow 1-5 Ohms
It would also do you good to buy a Clymer or similar service manual.
Do not buy a owners manual..
Just did this with my multimeter again with both stators on the bench. Using the connector end only I checked both red- white and then yellow - white/yellow.
One Stator #1 ( old stator ) Results:
White to Red 11.2 Ohms ( and yes continuity of course )
Yellow white to yellow 0. No continuity. Wouldn't beep. I messed around with it to ensure i had the meter fully inserted.
Stator #2 ( was brand new with a few hours of use before bike died )
White to red 0 .. no continuity.
Yellow / white to yellow 0... no continuity.
I think we have our culprit. What would cause a brand new stator to have this happen with only a few hours of riding since a brand new engine build.. Bike still is not running just wanted to post this online to see what your opinions are before i go and buy another part to throw at the bike haha
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What would cause a brand new stator to have this happen with only a few hours of riding since a brand new engine build..
no brand new part is guaranteed not to fail in a short period of time....especially electrical/ignition parts...that's why you don't get a warranty on them.
you may very well have just gotten a "lemon".
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So i Retested just then to make sure I did it right. Realized I did it partially right haha. It says to test Yellow/white to yellow.. I was checking yellow/white to white.
Old Stator ( #1 )
Pins Yellow/white to white = 2.3 Ohms
Pins White to Red = 11.2 ohms
Checked for shorts as well, no shorts. Appears to be working.
New stator ( Stator # 2 )
Pins yellow/white to white = 2.3 ohms
Pins white to red = no connection / no continuity.
I had a friend over to the house yesterday and we tried cranking the bike with the old and the new stator. Even with the old stator installed ( which i've just learned tested out fine ) still didn't produce a spark. I will try what you mentioned earlier and try swapping the ignition coil again
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Update!:
After realizing one stator ( the old one ) still should work i started troubleshooting again. Swapped out the spark plug again, took every ground off and cleaned it up then reconnected, swapped out the silver block on the next of the bike and Boom! I got spark.
Should have the bike running again today at some point. I am thinking it was a combination of the stator ( new stator ) being bad and the ignition coil needing to be swapped out. But it works now thankfully.
Thanks for all the help!
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awesome!
ignition/spark issues can suck...good to hear you got it firing.
throw up some pics when you get a chance.