[Brocster1007]

my 400ex has spark sometimes and sometimes not kill switch is unhooked green and the black white wire separated from the switch new coil just put on could it be cdi? stator? bad ground? ive tried everything I can think of I don't get stumped very often but I am this time

 

[kartl]

That is quite bad, but try to isolate the problems, change the spark plug then test, change the high tension wire then test, try to borrow a cdi before buying a new one.

 

[03xxxx300ex]

proby cdi or stator test stator with muti meter check for bad grounds an fraid wires if not stator or bad wire then try cdi

 

[Here 2 help]

Disconnect the key switch from the wiring harness. To get the engine to crank, connect the red wire to the black wire on the wiring harness side of the switch connector. If the spart is good, replace the key switch. If the spark is still intermittent - it will either be; the black wire with the white stripe shorting to ground somewhere, a poor wiring connection between the stator and the CDI box or between the CDI box and the coil, a sheared flywheel key or a defective stator.

 

[dnorthern]

I had an intermittent spark issue. Spark at the plug when I hit the start button and when I let off but nothing in between. The problem was the voltage regulator/rectifier was shorted to the body of the regulator/rectifier. I removed the regulator/rectifier from the frame and I had spark, runs great. Replacing the unit now.