YAMAHA BLASTER STATOR TEST FOR 4 AND 5 WIRE
A failed stator is one possible cause of a Yamaha Blaster having no spark, weak spark, intermittent spark or difficult starting. Before replacing the stator, CDI box or ignition coil, you can test the stator windings with a digital multimeter.
Yamaha used two different factory stator and ignition configurations during the Blaster’s production:
- 1988–2002 Yamaha Blaster: Four-wire stator
- 2003–2006 Yamaha Blaster: Five-wire stator
Although both stators perform the same basic functions, they are not tested exactly the same way. The pickup-coil specifications and source-coil test connections are different.
What Does the Yamaha Blaster Stator Do?
The Yamaha Blaster stator contains separate windings that perform three important jobs:
- The source coil supplies electrical power to the CDI ignition system.
- The pickup coil tells the CDI when to fire the spark plug.
- The lighting coil supplies power to the headlights and taillight.
The lighting coil can work even when the ignition portion of the stator has failed. Having working headlights does not prove that the stator is producing the correct ignition voltage.
Tools Needed to Test a Blaster Stator
You will need:
- Digital multimeter capable of measuring resistance
- Clean meter probes
- Access to the stator connectors
- Correct wiring information for your stator
The engine does not need to be running for these resistance tests.
Before Testing the Stator
Disconnect the stator connectors from the wiring harness. Do not measure resistance through the CDI box or the rest of the Blaster’s wiring.
Set the multimeter to the resistance setting, identified by the Ω symbol.
Touch the two meter probes together before testing. The meter should read at or very close to zero. Record the resistance of the meter leads because it can affect the very low lighting-coil measurement.
All factory resistance specifications are measured at approximately 68°F or 20°C. Copper resistance increases with temperature, so a hot stator may measure slightly higher.
How to Test a Four-Wire Yamaha Blaster Stator
The factory four-wire stator was used on 1988–2002 Yamaha Blasters. Its Black wire serves as a common connection for the stator coils.
| Stator component | Test between these wires | Specification at 68°F |
|---|---|---|
| Pickup coil | White/Red and Black | 72–108 Ω |
| Source coil | Black/Red and Black | 192–288 Ω |
| Lighting coil | Yellow/Red and Black | 0.16–0.24 Ω |
Four-Wire Pickup-Coil Test
Place one meter probe on the White/Red wire and the other probe on the Black wire.
The pickup coil should measure between 72 and 108 ohms.
Four-Wire Source-Coil Test
Place one meter probe on the Black/Red wire and the other probe on the Black wire.
The source coil should measure between 192 and 288 ohms.
Four-Wire Lighting-Coil Test
Place one meter probe on the Yellow/Red wire and the other probe on the Black wire.
The lighting coil should measure between 0.16 and 0.24 ohm.
Because this resistance is extremely low, subtract the resistance of the meter leads from the reading.
For example, if the meter reads 0.2 ohm with the probes touching and 0.4 ohm across the lighting coil, the actual coil resistance is approximately 0.2 ohm.
How to Test a Five-Wire Yamaha Blaster Stator
The factory five-wire stator was used on 2003–2006 Yamaha Blasters with the later CDI and TORS system.
Unlike the early stator, the later source coil is tested between the Green/White and Black/Red wires.
| Stator component | Test between these wires | Specification at 68°F |
|---|---|---|
| Pickup coil | White/Red and Black | 16–24 Ω |
| Source/direction-sensing coil | Green/White and Black/Red | 192–288 Ω |
| Lighting coil | Yellow/Red and Black | 0.16–0.24 Ω |
Five-Wire Pickup-Coil Test
Place one meter probe on the White/Red wire and the other probe on the Black wire.
The pickup coil should measure between 16 and 24 ohms.
This is considerably lower than the 72–108-ohm specification used for the original four-wire stator.
Five-Wire Source-Coil Test
Place one meter probe on the Green/White wire and the other probe on the Black/Red wire.
The source coil should measure between 192 and 288 ohms.
Do not test the Black/Red wire against the Black wire as you would on an original four-wire stator. On the factory five-wire system, the Green/White wire completes this circuit.
Five-Wire Lighting-Coil Test
Place one meter probe on the Yellow/Red wire and the other probe on the Black wire.
The lighting coil should measure between 0.16 and 0.24 ohm. Remember to subtract the resistance of your meter leads.
Four-Wire Versus Five-Wire Stator Specifications
| Test | 1988–2002 four-wire stator | 2003–2006 five-wire stator |
|---|---|---|
| Pickup-coil wires | White/Red to Black | White/Red to Black |
| Pickup-coil resistance | 72–108 Ω | 16–24 Ω |
| Source-coil wires | Black/Red to Black | Green/White to Black/Red |
| Source-coil resistance | 192–288 Ω | 192–288 Ω |
| Lighting-coil wires | Yellow/Red to Black | Yellow/Red to Black |
| Lighting-coil resistance | 0.16–0.24 Ω | 0.16–0.24 Ω |
How to Interpret the Test Results
The multimeter reading can indicate the following conditions:
- OL, infinity or no reading: The winding or a connecting wire may be open.
- Reading substantially below specification: The winding may be internally shorted.
- Reading substantially above specification: The winding may be damaged, or there may be corrosion or a poor connection.
- Reading within specification: The winding passes the resistance test, but this does not guarantee that it produces sufficient voltage when the engine is kicked over.
Inspect the wires, terminals and connectors carefully before condemning the stator. Corroded connectors, broken wires and poor grounds can produce the same symptoms as a failed stator.
What to Do If the Stator Fails the Test
If the stator is outside the correct resistance range, Ken OConnor Racing offers two repair options.
Complete Ken OConnor Racing Rebuilt Stator
The Ken OConnor Racing complete Yamaha Blaster stator is professionally rebuilt using a factory Yamaha stator plate and the Rick’s Motorsport Electrics Hot Shot components.
The rebuild includes:
- Source coil
- Pickup or trigger coil
- High-output lighting coil
- 75-watt lighting output
- Factory Yamaha backing plate
- Complete professional assembly
- Replacement wires
Using the factory stator plate maintains the original fit, wire routing and pickup location. This is a good option for someone who wants a professionally assembled stator instead of installing and soldering individual coils.
Rick’s Hot Shot Stator Rebuild Kit
For customers rebuilding their own factory stator, KOR also sells the Rick’s Hot Shot Yamaha Blaster Stator Rebuild Kit.
The Rick’s kit fits 1988–2006 Yamaha Blasters and includes:
- Source coil
- Pickup or trigger coil
- High-output 75-watt lighting coil
- Installation instructions
The rebuild kit does not include the backing plate. You must reuse your original factory stator plate and properly install, solder and route the new wiring.
What If the Stator Tests Good but There Is Still No Spark?
A Yamaha Blaster can still have no spark even when the stator resistance is within specification. Continue checking:
- Spark plug
- Spark plug cap
- Ignition coil
- Ignition-coil ground
- Black/White kill wire
- Key switch
- Handlebar kill switch
- TORS wiring
- Wiring connectors
- Flywheel magnets
- Flywheel woodruff key
- CDI box
Do not replace the CDI box until the stator, ignition coil, switches, grounds and wiring have been checked.
A damaged or partially sheared woodruff key may allow the ignition system to produce spark at the wrong time. Loose, broken or displaced flywheel magnets can also cause a weak or inconsistent ignition signal.
Important Information About Aftermarket Stators
Aftermarket wire colors are not always identical to the original Yamaha wiring. Never connect an aftermarket stator based only on wire color or the physical location of the terminals inside a connector.
Use the instructions supplied by the stator manufacturer and compare them with the correct Yamaha wiring diagram.
If a Blaster has previously been modified, identify the actual stator and wiring configuration before choosing which resistance specifications to use. Do not assume it still has the original stator based only on the ATV’s model year.
Frequently Asked Questions
Are Yamaha Blaster Four-Wire and Five-Wire Stators the Same?
No. The original four-wire stator was used on 1988–2002 Blasters, while the original five-wire stator was used with the revised 2003–2006 CDI and TORS system.
The pickup-coil resistance specifications and source-coil testing connections are different. However, some aftermarket rebuild kits can be configured for either system.
Can a Four-Wire Stator Be Used on a Five-Wire Yamaha Blaster if I Ground the Green Wire?
Yes. A four-wire-style stator can be used with a 2003–2006 five-wire Blaster ignition system when it is wired correctly.
When using the Rick’s Motorsport Electrics Hot Shot rebuild kit in a four-wire configuration, the Green/White wire from the five-wire harness must be connected to a clean ground on the stator plate, engine or frame.
The ground connection must be clean, tight and free of paint, oil and corrosion. A poor Green/White ground can cause weak spark, intermittent spark or a complete no-spark condition.
Always follow the instructions supplied with the stator or rebuild kit. Do not assume that every aftermarket stator uses the same wire colors or grounding arrangement.
The Rick’s Hot Shot Yamaha Blaster Stator Rebuild Kit is designed to cover 1988–2006 Yamaha Blasters when installed according to its supplied instructions.
Which Specifications Should I Use After Converting a Five-Wire Blaster to a Four-Wire Stator?
Test the stator according to the stator configuration that is actually installed—not simply the model year of the Blaster.
If a 2003–2006 Blaster has been converted to a four-wire-style stator, use the resistance specifications supplied by the stator manufacturer. The original factory five-wire test procedure may no longer apply.
Can I Test a Yamaha Blaster Stator Without Removing the Flywheel?
Yes. The basic resistance tests can be performed through the disconnected stator connectors.
The flywheel only needs to be removed when inspecting or replacing the stator, pickup coil, flywheel magnets or woodruff key.
Can a Stator Pass the Resistance Test and Still Be Bad?
Yes. A resistance test checks the stator windings while the engine is stationary. A stator may pass this test but fail to produce sufficient voltage while the engine is being kicked over.
Some stators also fail only after becoming hot. If the Blaster loses spark after warming up, test the stator both cold and immediately after the problem occurs.
Does a Working Headlight Prove the Stator Is Good?
No. The lighting coil and ignition coils are separate circuits. A Blaster can have working lights while the source coil or pickup coil has failed.
Does a New Stator Automatically Fix a No-Spark Condition?
No. A no-spark condition can also be caused by the spark plug, plug cap, ignition coil, kill circuit, TORS wiring, poor grounds, damaged connectors, flywheel, woodruff key or CDI box.
Testing each component is less expensive and more reliable than replacing parts at random.