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Replacing the Ignition Coil and Condenser on a Honda CT90 / Trail 90

Updated

 

On the Honda CT90, the ignition coil and condenser are hidden deep within the frame unlike the CB100 or CB125. They’re bolted together in the frame, under the gas tank, and behind the battery. Since getting to them takes some work, it’s usually a good idea to replace both parts at once if either one is bad.

Compatibility

Our ignition coil fits all CT90 models.

 

What to Remove First

You don’t have to take off all of these parts, but doing so makes the job easier:

  • Brush guard or skid plate

  • Muffler

  • Air filter

  • Gas tank bolts (then tie the tank up and out of the way)

  • Side cover

  • Disconnect and remove the battery

  • Battery tray front bracket

How to Install the New Ignition Coil

  1. Buy our Ignition Coil and Condenser here

  2. Remove the Old Parts:
    • Unscrew the two nuts under the gas tank that hold the coil and condenser in place inside the frame.
    • If you’re only replacing the condenser, you can swap it out now and put the coil back without doing the rest.

    • Unscrew the spark plug boot.

    • Pull the spark plug wire out of its clamp on the engine.

    • Feed the wire back through the frame so you can fully remove the old coil.

  3. Install the New Coil:

    • Feed the new spark plug wire through the frame and out near the left side of the carburetor.

    • Mount the new coil using the same bolts and washers.

  4. Route the Spark Plug Wire:

    • The original path for the wire goes near the hot exhaust pipe, which isn’t ideal.

    • We recommend routing the wire over the engine and then down to the spark plug. This keeps it away from heat and looks cleaner.

  5. Trim the Wire:

    • Leave a couple extra inches in case you need to cut it shorter in the future.

    • Once you’re sure about the length, cut it.

    • Screw the spark plug boot onto the end of the wire and connect it to the spark plug.

  6. Set the Timing:

    • Even if you’re getting spark, it might not be firing at the right time.

    • Be sure to set the ignition timing correctly so the engine runs properly.

 

Since you’ve already removed so many parts, check out our repair guides of the other jobs worth doing while you are in the same area:

Reassemble the motorcycle and you are ready for a ride!

 

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