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Join Date: Jan 2011
Location: Smack in the middle of Illinois
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The CDI box you got (30410-HM5-505) is for 94-97 TRX300 and TRX300FW
The CDI box you need is 30410-HC4-770 - they are both DC voltage modules, but they are not compatible or interchangeable. They are designed to operate with different values of peak voltage. They have the same plugs and wires except the 93 has a blue/white wire and a gray wire where the 94-97 has a black white and a green wire on the two pin connector. If you trace the wires, the blue/white of the 93 plugs into the black/white to the handlebar engine stop switch (the 94-97 plugs into the same place they just used different color wires). The blu/wht of the 93 and the blk/wht of the 94-97 both have 12v+ on the wire when the handlebar engine stop switch is in the on or run position.
You should have ground on the gray wire only when the transmission is in reverse.
However, before you get a different CDI module, you need to have a peak voltage tester to determine what the problem actually is. Retest everything using the old CDI box and if you determine the CDI box is the culprit, then get the right one. See if you can rent or borrow a multimeter with a peak voltage function - or an oscilloscope - or a peak voltage adapter for a standard multimeter. Checking resistances is one step of the process, but knowing the peak voltages is key to determining the problem. With a peak voltage tester, you can actually measure the output of the coil to the spark plug.
Generally, the stator fails, the flywheel key shears or another component is responsible for loss of spark. Frequency of failure resulting in loss of spark is; 1) spark plug 2) spark plug cap, 3) wiring connections, 4) switch, 5) battery, 6) stator, 7) pulse generator, 8) CDI module, 9) coil, 10) flywheel key (spark timing), 11) something else.
What have you tested and what were the results of each test?
I can email you the manual or pages from the manual if that would be helpful. Just PM me your email address.