Ignition Condenser | Honda CT90 / Trail 90

Description

Ignition Condenser | Honda CT90 / Trail 90

The condenser is one of the most failure-prone parts of the CT90 ignition, and a tired one takes the points down with it. It has no moving parts, but it still wears out with age — and when it does, the bike idles but won’t rev, and fresh points burn up fast. A new condenser puts the spark back where it should be.

Why You Need This

The condenser works alongside the contact points and the ignition coil: it protects the points from arcing and keeps the coil charged at higher rpm, so the spark plug fires a strong, consistent spark. Even a CT90 that looks mint can have a condenser that’s quietly decayed. The classic signs of a failing one are an engine that idles fine but won’t rev up, and contact points that burn out after just a few hundred miles.

Specifications

How to Tell If Your Condenser Is Bad

Pull the points cover and watch the points in a dark spot as the engine turns them open. A bright spark or arc jumping across the points each time they open points to a bad condenser; a small spark every few seconds is normal. If you have a multimeter, a healthy condenser reads high resistance — around 5 MΩ or more — while a shorted one reads very low.

Installation

The condenser grounds through its mounting tab, so clean the surface where it bolts to the frame for a solid ground — a poor ground is as bad as a dead condenser. If a previous owner has rewired the bike, you may need to re-route the wires at the ignition coil so everything lands where it should.

The condenser lives with the coil down inside the frame. You can see the whole job in our CT90 coil-and-condenser video: