los coil de mi moto no estan dando la chispa, por un instante lo hace luego no. mi mecanico dice que es el CDI o computadora de la moto que tiene el fallo ke puedo hacer. {Reiny, Santa Domingo, Dominican Republic 1987-88 Suzuki GSXR1100}

The general gist of this question is the coil on his GSXR1100 has intermittent spark and his mechanic said either the CDI or computer is at fault and what do we think.

The cause of your intermittent spark is one of the ignition coils, signal generator {pulser coil} or igniter {CDI}. You will need an electrical multi-meter to perform the required tests. If you do not have one, you can purchase one online. Try Autogeek.net or NorthernTool.com.

The ignition system of your GSXR1100 consists of a signal generator, computerized ignitor unit or CDI, two ignition coils and spark plugs. The signal generator is mounted at the right end of the crankshaft. It sends a signal to the igniter which uses a microcomputer and a read only memory {ROM} chip to calculate the best ignition timing. The igniter then sends a signal to the primary windings of the ignition coils, to turn off and on accordingly. This creates current on the secondary windings of the coil which travels down the plug wires and produces the spark in the spark plug gap.

A failure in any one of these components can cause the bike to exhibit intermittent spark.

In this system, you can not test the igniter {CDI} directly. You can test the ignition coils and the signal generator. If one of these components fails, replace it. If they both pass, replace the igniter.

To access the ignition coils, first remove your seat and fuel tank. Then remove the coils.

The ignition coils need to be checked for continuity in both the primary and secondary windings. The primary winding is accessed via the positive {+} and negative {-} taps on the coil. They look like two small tabs sticking up on the end of the coil. Make sure your multi-meter is set to Ohms, the Ω symbol. Place your positive lead on the positive tap, negative lead on the negative tap of the coil. Your meter should show an ohmic continuity (resistance) value of between 2.4 and 3.2 Ω. Be sure to test both coils.

Next, test the secondary windings via the plug boots {aka spark plug caps}. This test is measured in kilo-ohms. Depending on the type of multi-meter you have, you may have a setting for kΩ, or the screen may display the k or a 10 to the power of 3, to the right of the numbers. Place one lead in each boot, your meter needs to display a value of between 30 and 40 kΩ. Again, be sure to test both coils.

Now, test the signal generator. The seat is already off the bike, so just disconnect the lead wires. They are yellow and blue. You will be measuring the resistance between the two wires on the 100Ω setting. If your meter displays a value of less than 135Ω or reads infinity {∞}, also called wide open, the signal generator must be replaced. Ideally, the signal generator resistance should be between 135 and 200 Ω.

Suzuki OEM Part Numbers:

Once you determine the faulty component causing your intermittent spark issue and replace it, be sure to install fresh spark plugs, properly gapped at 0.6 to 0.7mm {.024 - .028 inches} before running the bike. People are always surprised at how different a bike runs when it has dirty or mis-gapped plugs.