Question about Yamaha Motorcycles
I have an 87 Virago 1000cc I know I need to sync the carbs but why do I lose power when I have it idling to warm it up before I ride? I have it plugged up to a battery charger when I don't ride for a while, I know that was one of the problems, but I start it up a few times and the battery dies again. But also smoke comes out of the top exhaust pipe but not the bottom exhaust... need some answers please and thank you!
Posted by Anonymous on
Hi, Anonymous before testing any electrical component in the Charging System it is "IMPERATIVE" that you have a fully charged battery of 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a preliminary reading of 12.5 volts or more but little or zero amperage, the battery is faulty and must be replaced. AGM type batteries fall into this scenario more so than lead acid batteries.
1. Battery Test:
The battery needs to be a fully charged and load tested to ensure proper readings, connections need to be clean and tight. If you are not working with a fully charged and functional battery, all other voltage tests will be incorrect. Standing battery Voltage should be 12.5-13.2 DCV.
2. Charging System Voltage Test:
Start motorcycle, measure DC volts across the battery terminals you should have a reading of approximately 13.2-15 DC Volts.
3. Connections and wires:
Inspect the regulator stator plug, and check the battery terminals for connection corrosion. If everything seems to be in order, move on to number 4 below to determine if there's a failed component.
4. Stator Checks/Rotor Check: Each of the following tests isolates the Stator & Rotor. If AC output and resistance test fail and stator test passes then the rotor is at fault (Pull Primary covers and inspect rotor for damage).
5. AC Output Check:
Unplug the regulator plug from the stator start motorcycle and change Voltmeter to AC volts. Probe both stator wires with your meter lead. The motorcycle should be putting out approximately 18-20 ACV per 1,000 rpm. Reading will vary depending on system, check service manual specification
22 amp system produces about 19-26 VAC per 1,000 rpm
32 amp system produces about 16-20 VAC per 1,000 rpm
45 amp system produces about 19-26 VAC per 1,000 rpm
Stator Resistance Check:
Switch your multimeter to Ohm x 1 scale. Probe each stator wires with meter leads and check resistance on the meter.
Resistance should be in the range of 0.1-0.5 Ohms. Reading will vary depending on the system, check the service manual for specifications.
22 amp system produces about 0.2 to 0.4 ohms
32 amp system produces about 0.1 to 0.2 ohms
45 amp system produces about 0.1 to 0.2 ohms
5. Stator Ground Check:
Switch your multimeter to Ohm x 1 scale.
Probe each stator wire with your positive lead on the multimeter and the negative to ground.
There should be no continuity to ground on either wire.
If there is continuity your stator is shorted to ground and must be replaced.
6. Regulator Test:
Each of the following tests isolates the regulator only, so if any of these tests fail, the regulator is at fault.
Battery Charge Lead- Wire going from the regulator to battery positive.
AC output leads- Wires coming from the Stator to the regulator.
Ground- Wire from Regulator to ground or regulator may be grounded via the physical bolting to chassis.
Regulator Ground Test: Ensure the regulator body is grounded or grounding wire is fastened tightly to a good ground (you should verify this by checking continuity from the regulator body to chassis ground).
Fwd/Reverse Bias Test/Diode Test:
This check is testing the Diode function to ensure it is regulating the AC current for the stator into DC Current.
Switch multimeter to Diode Scale.
Place your Multimeter positive lead on each AC output wire.
Place your multimeter negative lead on the battery Charge wire.
The meter should read voltage typically around .5 volts.
Next, switch your multimeter leads putting the negative lead on the AC output wires and the Positive lead on the Battery Charge Wire. The reading should be Infinite. With your meter on the same setting, place your multimeter positive lead on the regulator ground wire or to the regulator directly, and then place your meter negative lead on the AC output leads.
The meter should read voltage typically around .5 volts.
Next, switch your multimeter leads putting the negative lead on the regulator ground and the Positive lead on the AC output wires. The reading should be Infinite.
Note: Below is a table to show the readings:
Positive Lead Negative Lead Reading
AC output 1 Battery charge lead Voltage
AC output 2 Battery Charge Lead Voltage
Battery charge lead AC output 1 ?
Battery charge lead AC output 2 ?
Ground AC output 1 Voltage
Ground AC output 2 Voltage
AC output 1 Ground ?
AC output 2 Ground ?
For more information about your issue and valuable "FREE" downloads for viewing and printing that you will need please click on the blue links below. Good luck and have a wonderful day.
OEM parts for Yamaha
Yamaha Virago XV1100L Owner Manual
Posted on Jul 17, 2017
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Posted on Jan 02, 2017
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