Honda TRX ATV Forum banner

21 - 23 of 23 Posts

Super Moderator
4,117 Posts
Sorry you got a wrong CDI unit and had so much trouble, but glad you got it figured out. Let me know if you ever need help again.

1 Posts
Breaking out spark issues from on this bike from the transmission thread.

Last year this machine started having intermittent spark. It seemed temperature related... on super cold mornings there would be no spark. Other times it would start and run fine. After ruling out carb issues I noticed no spark. I immediately tried a new spark plug. No spark.

After reading nearly every "no spark" thread I could find, it seemed the easiest thing to start with was a replacement CDI. I really thought it was the CDI, and temperature or maybe humidity was causing microscopic shorts or something. The CDI I bought came with a new coil so I swapped out both. Still no spark.

I unhooked the pickup coil and stator and ran resistance and continuity checks and they were within spec. I found a post mentioning a stator that tested good, but when inspected it had burnt wiring and was actually bad. I pulled the stator cover and inspected the stator. It visually looked fine, and I retested and it looked fine. As long as I had the stator cover off I decided to replace the pickup coil as they are fairly cheap and I know they start to fail around this age anyway.

Still no spark. I retested the CDI wiring via the manuals CDI trouble shooting section (including picture of the tests and expected values I used). One thing I noticed is the shop manual wiring mentions a Y/W wire which I do not have. I am including a picture of the wiring on this machine.

My values on CDI wiring are:

BL/Y and G: .2 ohms
Bu/Y and G: 340 ohms
Bl/W and G: 12.7 volts
Gr and G: No continuity
Y/W and G: I dont have Y/W wire
YW and Y: I dont have Y/W wire.

I got a 2nd CDI on the chance of the first one being bad, still no spark. I cant imagine both new CDI are bad along with the OEM.

IDK where to go from here, what to test next.

Old post but it’s your cdi. Don’t buy cheap China replacement parts. Order a ricks cdi. I’ve fixed tons of no spark machines that have “new” cdi on them. Oem or ricks only. Don’t remember what machine you have now but they are model specific. Fourtrax and foreman 350 models there are 3 differnt Cdi models and fourtrax 300 has 3 differnt generations year cdi. First gen 1988-1993 are first gen

21 - 23 of 23 Posts