How to Charge a Honda Trail 90 Battery

The Honda Trail 90 motorbike was manufactured from 1964 to 1979. It has a lead acid, 6-volt, 5.5-Ah battery and an electrical ignition system. Starting relies on the bike having a fully charged battery. Most original batteries have long since died and been replaced with compatible alternatives offered by a range of manufacturers. Charging the battery requires access to a 6-volt battery charger, a few simple tools and minimal mechanical and electrical knowledge.

Step 1

Identify the leads attached to the battery. The original wiring uses a red wire for the positive lead and a green wire for the negative lead on all versions of the CT 90. Disconnect both leads from the battery, positive lead first, using either a screwdriver or a spanner depending on the type of battery clamp on the wires.

Step 2

Clean the battery terminals with a wire brush to remove dirt and corrosion that would interfere with the battery charger connections. Check the electrolyte levels in the battery cells, and top up if necessary. Use only distilled water or "battery water." If a cell is dry, consult the manufacturer's recommendations before refilling it.

Step 3

Attach the battery charger to the positive and negative battery terminals. Ensure that the charger clamps are correctly polarized and have a good grip on the battery terminals. If your charger has the facility, set it to charge at the lowest amperage it allows, ideally 2 amps.

Step 4

Switch on the battery charger and observe the battery and charger at regular intervals over the next few hours. When the meter on the battery charger indicates the charge is complete, switch off the charger. Remove the charger wires from the battery, positive first, and then negative.

Replace and securely attach the green negative battery lead, then do the same with the red positive lead. The battery is now fully charged and reconnected to the bike.


Remove the battery from the bike at step 1 to charge it in a garage or shed. This may be easier if you can't park the bike close to a power socket.

Clean the battery and battery tray with a mixture of baking soda and water to neutralize any acidic residue from the battery.


Remove all jewelery and metal watches before working on batteries. Metal conducts and accidental contact with the battery could result in an electric shock.

Do not smoke near a lead acid battery. Lead acid batteries may release hydrogen while charging. A spark or flame may trigger an explosion.

Items you will need

    Battery charger for 6-volt batteries
    Small wire brush
    Spanner to fit the battery terminals
    Distilled or "battery" water