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Hi guys,

mom hoping to get a bit of help. My trx 300 big red runs fine then all of a sudden dies.

if I turn the ignition on and of the bike fires then dies. Does this a lot then all of a sudden runs fine.

I have taken spark plug out and when doing this it sparks at first then stops sparking if I continue to crank it.

if I turn ignition off and on again it then sparks for a second then stops as I continue to crank.

many help is appreciated.

Thanks Chris
 

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3,571 Posts
The ignitions have changed from model to model.

Give us some more info - what year model, 2WD or 4x4 - VIN if possible
 

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OK - your unit has a DC ignition (no spark without voltage) - knowing that; an intermittent spark is usually a poor wiring connection and intermittent problems are the hardest to find. The probability of low voltage to the CDI unit exists.

If cleaning wiring connections (especially ground connections) does not solve the issue, then start checking voltages. If the voltage on the black/white wire at the CDI unit drops below 10.5 volts while cranking the engine, then spark can be sporadic. The pulse coil may have a poor connection inside the engine. It can be checked externally by checking the peak output voltage with a peak voltage tester while cranking the engine - typically 3 to 5 volts per pulse. If this passes muster, then check the output voltage of the CDI unit - the black/yellow wire from the CDI unit to the coil is typically about 100 volts per pulse - the output to the spark plug is about 30 - 40,000 volts per pulse. If all is good to this point, nothing is ruled out, but the probability is good that the problem is spark plug cap, spark plug or engine to frame ground.

This may not resolve the problem, but it will narrow the remaining probabilities.
 
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