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no spark from plug

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Sep 16, 2001
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#1
The 2000 ktm 300exc bike died on me while I was out putt-putting around this weekend, it was at idle when it died.

I let it sit for a few minutes, cooled down myself, and kicked it once and it started right up.

I rode another 2 or 3 miles deeper into the woods (big mistake) and it died again. Same as before, I was at idle taking a qwik drink from the water bottle. It would not restart. I had to push it 5 miles out of the woods.

I got home, replaced the spark plug (black and sooty) with an older one (also black and sooty), and it cranked on the first kick (unusal for me). I rode to the end of the driveway and it died again. It would not restart.

I put new a plug in it today and nothing... I pulled the plug, grounded it good, and tried kicking. No spark...

Any words of wisdom on what to look for next? I have a spare 300exc so I can pull parts from the spare and try things before spending the big bux.


ps: is the CDI unit the black-square-looking thingie mounted up on the frame just under the handlebars, near the top of the gas tank?

-pat-
 

Shaw520

Damn Yankees
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#2
Originally posted by TooOld


ps: is the CDI unit the black-square-looking thingie mounted up on the frame just under the handlebars, near the top of the gas tank?

-pat-
Yes it is, and from your description, I would say 'the black-square-looking thingy' is the culpret!
 
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#3
Re: Re: no spark from plug

Originally posted by Shaw520

Yes it is, and from your description, I would say 'the black-square-looking thingy' is the culpret!
any idea what a cdi is gonna cost me? will I need a second job?

-pat-
 
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#4
You have checked the simple things, right?
(Example, cleaned up all wire connections leading to the coil and cdi, Taken off sparkplug cap and rethreaded it, looked for wires grounded on the frame ect.)

Just making sure,

Danny
 
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#5
it works now !! ???

Originally posted by Danny8785
You have checked the simple things, right?
(Example, cleaned up all wire connections leading to the coil and cdi, Taken off sparkplug cap and rethreaded it, looked for wires grounded on the frame ect.)Just making sure,
Danny
Damnest thing...

I went to change the CDI but first decided to check that spark one more time. Bingo, I saw spark. I put the plug in, kicked it once (with sandals on) and it fired right up. Now what?? I killed it and tried again, and again, it started right up on first kick.

Dunno if a CDI can go bad, then good, then bad and then back to good again but I'll ride it this week and see if it acts up again.

Maybe I pulled the spark plug wire too hard when I was removing it? Maybe it wasn't plugged in all the way?? Dunno... we'll see this weekend.

Thx for your note. I'll let ya know how it turns out.

-pat-
 
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#6
when i was restoring an old yz 80, i didn't get any spark and i thought the cdi
unit was bad, and those things aren't cheap. so i started looking for a new
one. before i was gonna spend a few bills on a new one, i took all the connections off and cleaned them up good. then tried it once more and found some spark. bike still runs fine.

danny8785 is probably correct, i would go over all the connections, maybe even replacing the engine kill switch, and you probably won't have any more problems.
 

Shaw520

Damn Yankees
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#7
Too Old, Checking all connections is step one before replacing parts, but keep in mind that CDI units and coils can and will malfuntion only when they reach operation temperature. So it may have spark and start, but when it gets hot! You may be pushing again!
 
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#8
CDI MAYBE but heat/vibs can make the until fail. I would go over all electrical connections FIRST. CDI's will set you back $300-$400. Look for simple things first.
 

Jaybird

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#9
My money is on the kill switch being corroded...or the spark plug wire not seated in cap good.
 
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#10
TooOld - A rider buddy with a 2000 300exc had a stator failure three weeks ago.

Bought a rewound stator, bike runs perfect.

Make sure you have disconnected the kill switch before you go any further.

Buddy's email is bdooley@wlgore.com if you wanna find out where to get replacement parts.

Bret's bike has over 4000 miles of singletrack racing on it....
 
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#11
Oh ya, Bret is like first or second Open A in the national enduro series this year, and is an engineer, so he both rides great and knows his stuff. Tell 'em Buck sent you (I work with him).
 
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#13
When I bought my 01 250exc it lost spark intermittently the first day for seemingly no reason. I removed the tank and checked the ground tab on the frame. It was rusted. I cleaned off the rust, applied some dielectric grease,reassembled everything and have had no problems since. Don't rule out the simple stuff. My dealer should have caught this since he said they had been having trouble with the kill switch when I went to pick it up but told me it had been fixed.