Ignition Coil & Condenser Kit | Honda CT90 / Trail 90
If your CT90 is hard to start, won't idle, or has a weak spark that looks dull white or yellow instead of bright blue, your decades-old factory ignition coil has likely worn out. This complete kit includes a new ignition coil, condenser, and spark plug boot — everything you need to restore strong, reliable spark to your Trail 90.
Why You Need This
Ignition coils degrade over time, producing weaker and more irregular sparks until they fail completely. Most CT90s are still running on their original coil from the 1960s or 1970s. A fresh coil delivers a stronger spark, which means easier kick-starting, smoother idle, and better performance across the rev range.
This kit also includes a new condenser — one of the most failure-prone electrical components on the CT90. Even if your coil is the primary concern, replacing the condenser at the same time makes sense because both parts are buried deep inside the frame, under the gas tank, and behind the battery. Getting to them requires removing several components, so doing both jobs at once saves significant labor. Extra condensers are available as an optional add-on so you can keep spares on hand.
If your ignition troubles persist after replacing the coil and condenser, check your spark plug and ignition contact points next.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Part Numbers | 30530-102-780 (coil), 30500-128-013 (coil), 30250-052-000 (condenser), 30700-MG7-000 (boot) |
| Fits Models | CT90 K0–K9 / Trail 90 (1966–1979) |
| Sold As | Complete kit (coil + condenser + spark plug boot) |
| Voltage | 6V |
What's in the Kit
- Ignition coil (1)
- Ignition condenser (1)
- Spark plug boot (1)
Installation
Difficulty: Intermediate — requires removing several components to access the coil inside the frame.
- Disconnect the battery. Remove the spine cover, air filter box, and brush guard/crash guard.
- Remove the muffler — spray the header pipe nuts with penetrating oil first, as they tend to be very rusty. There are two bolts at the cylinder head, one at the gas tank stud, and one at the rear shock mount.
- Unbolt the gas tank and tie it up out of the way (you do not need to fully remove it).
- Remove the battery and battery tray front bracket for clearance.
- Unbolt the old coil (two nuts hold it inside the frame). Disconnect the black/white stripe wire (positive) and the green wire (points connection).
- Unscrew the spark plug boot and pull the old spark plug wire back through the frame.
- Feed the new spark plug wire through the frame tube and out near the cylinder head.
- Mount the new coil with the condenser pointing toward the rear and the wire toward the front. Reconnect the black/white stripe wire and green wire.
- Thread the spark plug boot onto the wire end — the boot has an internal screw that threads into the wire like a corkscrew. Push and twist until seated.
- Set the ignition timing. Even if you get spark immediately, the timing may not be correct for proper engine operation.
Wire routing tip: The factory routing runs the spark plug wire close to the exhaust, which exposes it to heat. We recommend routing the wire over the top of the engine and down to the spark plug instead. This keeps the wire away from the exhaust and cylinder fins.
Our CT90 ignition coil and condenser replacement video walks through the complete job — what to remove, how to fish the spark plug wire through the frame, alternative wire routing to keep it away from the exhaust, and reassembly.
Frequently Asked Questions
How do I know if my CT90 ignition coil is bad?
Pull the spark plug and ground it against the engine, then kick the engine over and watch the spark. A healthy coil produces a bright blue or purple spark. A weak coil produces a dull white or yellow spark, or no spark at all. Per the Honda service manual, the coil is normal if sparks jump across a gap of more than 6mm (0.24 in.) during a 3-point spark test.
Does this kit include the condenser?
Yes. The kit includes a new ignition coil, condenser, and spark plug boot. Since the coil and condenser are both buried inside the frame and require the same disassembly to reach, we include both so you can replace them in one job. Extra standalone condensers are also available here.
Will this fit my CT90 regardless of year?
Yes. This ignition coil fits all CT90 models from K0 (1966) through K9 (1979).
Do I need to set the ignition timing after installing a new coil?
Yes. Even if the engine fires right away, the timing may be off. Set the ignition timing after installation to ensure the engine runs properly. See our CT90 ignition timing guide for step-by-step instructions.
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Last updated: March 2026
