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TRX 250 No Spark

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26K views 11 replies 5 participants last post by  Lil nay atv  
#1 ·
Had a family member drop off their recon again the other day. It has been losing spark intermittently. Typically, it starts up fine and will run for 1 hr+ then, all of a sudden, it will start to miss, then it dies. If you wait awhile (1/2 hr or longer) it will usually fire back up and run like nothing ever happened.

2 weeks ago they had it out, it did the usual as described above but, never started back up. They brought it to my garage the other day. I checked spark and verified there was no sign whatsoever.

I pulled all the plastic and started taking apart connections. I pulled the connectors off the ICM, R/R, neutral switch connectors, etc.... whatever I could find in the ignition circuit. I cleaned them all up and added some dielectric grease. I removed the spark plug cap and trimmed the wire. After that, I tested spark again and found a nice, fat, blue spark. Put the plug wire back on the plug in the engine and it fired up instantly.

I have mixed feeling about this. Its great that it fires up but, I'm concerned that I didn't actually fix anything. I'm thinking its going to do the same old routine once it gets out on the trail.

Anybody have an idea as to what part usually goes bad that prevents spark? ICM, Coil...? I read through the manual but, I don't have a peak voltage tester so I'm not sure how I can verify what component is causing the problem if it does reappear.

On another note, does anyone have any tricks for releasing the electrical connectors from the frame of the guad? They have a tab that locks them in place on the frame. I was successful in removing a few by inserted a feeler gauge in there to depress the tab and they slid right off. On a few, I can't get the feeler gauge in there as it is too wide. Is there a special tool to release them?

I have no problems removing the male from the female side. My problem is getting them off the frame. I like to do that so I can hold them upside down and spray electrical cleaner in there and let it drip out.
 
#3 ·
Understood. I used the dielectric grease on all connectors I could find associated with the ignition. Plus a couple extras I'm sure.

When I took them apart, there was no sign of corrosion on any of them. Sure they were dirty on the outside but the inside all looked fine. I'm not sure what caused the spark to come back.

I'm thinking about just replacing the ICM for peace of mind. Its not that expensive and I'd rather not tear this thing apart again!
 
#5 ·
I would agree with da Moose on the cdi being the culprit as they are known to stop working when they get hot,hence it dying after riding it a bit,and that is typically the main sign that the cdi is dying,and will fail completely before too much longer...If it were an older atv like a 1988-200 trx300 I would also throw in cleaning the run/off switch using spray electrical cleaner sprayed into the switch as you press it in,and switch it back,and forth rapidly...
 
#8 ·
The new CDI came in a few days after my last post. I had all the plastics off so I cleaned up nearly every connector, put in dielectric grease, cleaned out the kill switch switch, removed grounds and cleaned the frame and terminals with a brass brush. I use a product called no-ox ID on the grounds to promote conductivity and eliminate corrosion.

The quad has been out a few times since then. So far all has been good. The real test will be labor day weekend. The whole extended family will be going camping for 4 days and we ride the better part of 2 of them.