# Kyoto2.org

Tricks and tips for everyone

# Can you convert AC CDI to DC CDI?

## Can you convert AC CDI to DC CDI?

This circuit turns an AC-CDI into a DC-CDI. This circuit was designed to bypass the faulty stator by making High Voltage (around 150 to 400V) directly from the +12v battery. When the internal SCR of the AC-CDI has been latched in ON state for a spark, only the voltage crossing a falling zero will turn it OFF again.

What is the main difference between an AC CDI and a DC CDI?

Your CDI has two plugs, a 4-pin and a 2-pin. The 4-pin side may have 3 or 4 wires connected to it (both AC and DC versions). If the 2-pin connector has only 1 wire going to it, it’s a DC CDI. If there are 2 wires attached to the 2-pin connector, then it’s an AC CDI.

### How does an AC CDI work?

In a CDI system, a charging circuit charges a high voltage capacitor, and at the instant of ignition, usually determined by a crank position sensor, the system stops charging the capacitor, allowing the capacitor to discharge its output to the ignition coil before reaching the spark plug.

Can you bypass CDI box?

You can bypass the kill switch on a 5 pin CDI by removing the center pin from your CDI connector or just cutting the wire. Once the kill switch pin or wire is no longer connected to the CDI connector, then you can plug it back in and try starting the engine.

#### How does a CDI get power?

A typical CDI module consists of a small transformer, a charging circuit, a triggering circuit and a main capacitor. First, the system voltage is raised to 250 to 600 volts by a power supply inside the CDI module. Then, the electric current flows to the charging circuit and charges the capacitor.

Can you run a bike without CDI?

The CDI is a vital component of the bike’s ignition system. Without the CDI – the bike cannot run and there is no way to bypass it. Unfortunately, testing a CDI directly is not really possible, therefore it’s always done using the elimination method.

## Do non-battery scooters need an AC regulator?

In traditional generator ignitions used as standard on many Vespa and Lambrettas this AC output is fine because old-style incandescent bulbs are dirty slags. They don’t care which end they get their electrical current from. As such, all that is required on non-battery scooters is to fit an AC regulator.

What does a clean DC circuit mean?

In simple terms, it means that electricity on a DC circuit flows only in one direction. This is the sort of output you get from a battery. Complex electrical items like sat-navs and phones are a bit fussy and will only operate off a clean DC supply.

### Can you convert a full AC system to DC?

We carried out the conversion and it worked perfectly, apart from one aspect; the horn. Horns tend to come in either AC or DC flavours, so if you convert a full AC system to DC then the chances are that you will need to change your horn as well. What problems might you encounter?

Do I need a regulator-rectifier for my scooter?

For our use, on a scooter without a battery, then it is better to have a regulator-rectifier with the added filtering circuitry; particularly if you intend to use this system to charge expensive accessories such as mobile phones.