Honda CR250 no spark

JMX82
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Edited Date/Time 8/13/2014 2:24am
My brothers 2002 CR 250 lost suddenly its spark. We have tried it with new spark plug and killswitch disconnected with no results. After that we discovered that the wires coming out from the CDI unit where peeled and might have gotten contact with each other. Will short circuit of these wires cause CDI unit to go bad? Should I try to change the ignition coil first? What is the easiest way to test ignition system components?

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Paw Paw 271
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5/20/2014 11:32am
The CDI can short out and the wires do look very bad, I suspect they grounded out on the frame. Seal each wire up and the wrap the bundle. I would also suggest that you check all the wires for more places like that.
I would also do an ohms test on the coil and clean the coil mounts. Then unscrew the spark plug cap from the wire, trim 1/4" off the wire and then screw the cap back into it. Now check to see if you have spark. The spark should be a very bright Blue in color. If it is any other color you still have issues. If the coil readings are good and you still have no spark, check the stator OHMs readings and it's wiring. Make sure the flywheel is good and clean.
If after all these items prove to be good then you may have a bad CDI. Most dealers can't test them.

Paw Paw
JMX82
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5/22/2014 12:03pm Edited Date/Time 5/22/2014 12:07pm
I found ignition coils resistance values from Honda's service manual and I measured the ignition coil resistances with digital multimeter. Here are the results:

Resistance between primary terminal and body ground 0.1-0.3Ω



Looks to be in tolerance



Resistance between primary terminal and spark plug cap 9-16Ω



Looks like it's way too much resistance here... 10.44 kΩ



Resistance between primary terminal and spark plug wire 4-8Ω




Too much resistance here also, 5.28 kΩ. I guess the problem is bad ignition coil?



Pick up coil seemed to be fine. I haven't pulled out the flywheel yet to check out the stator coils


mx5471
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5/22/2014 5:38pm Edited Date/Time 5/22/2014 5:40pm
It's 99% never the coil. Replace the CDI and it will live. I tiny short will fry it.
JMX82
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5/22/2014 11:56pm
I broke my 2010 KTM 150SX ignition coil a couple years ago. The bike suddenly died same way as my brothers Honda. (I was middle of frozen lake riding with studded tires and had to push the bike trough thick snow to get to the shore) I had spare ignition coil in the garage and the bike came back to life after I changed the coil.

I think Honda has the same CDI box only in 2002 and 2003 models so it's really hard to find used one and the new CDI is pretty expensive. I really hope that we don't have to replace that.

The Shop

JMX82
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5/24/2014 12:30am
We decided to order new ignition coil to the bike. All other components resistance values where in factory limits. CDI unit couldn't be measured with out Honda's special tool so it's either bad ingntion coil or CDI.
Cygnus
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5/24/2014 7:26am
JMX82 wrote:
We decided to order new ignition coil to the bike. All other components resistance values where in factory limits. CDI unit couldn't be measured with out...
We decided to order new ignition coil to the bike. All other components resistance values where in factory limits. CDI unit couldn't be measured with out Honda's special tool so it's either bad ingntion coil or CDI.
You can test the coil on another bike pretty easy. I would before I spent the $ for a new one.
Paw Paw 271
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5/29/2014 2:35pm
I would unscrew the plug cap from the wire, then cut 1/4" off the wire and screw the cap back in place and then retest the ohms readings. They should be better if the coil is ok. You may even now have spark.
Matt Fisher
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5/29/2014 3:58pm
If you end up needing ignition parts I have all of them from my 03 CR250 that I parted out. Shoot me a PM.
JMX82
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6/5/2014 2:51am
We tried the bike with the new coil and still no spark. I guess the CDI unit has gone bad. Is there any aftermarket ignitions for last generation CR250's with RC valve available? New oem CDI unit costs here in Finland 394 EUR (535USD) at the local parts dealer.


Matt Fisher PM sent
cslacker
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6/6/2014 12:09pm
Zeeltronic makes a programmable unit for the CR250.
JMX82
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8/13/2014 2:24am
We got the bike running, thanks to used CDI unit from Matt Fisher.

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