not charging

[rollinghelmet]

I think my alternator is bad battery voltage is not increasing when i rev engine
I checked alternator brushes and they are good, fuses are fine

What is the next thing to test, can anyone suggest past post or refer me to haynes manual thanks

[CutterBill]

Check the red connector under the battery for corrosion; it must be perfect. What is the battery voltage reading?
Bill

[rollinghelmet]

Red plug is good Battery voltage is 13.1 just charged with ac charger
When running battery voltage is 13 does not increase when rev engine
With alternator plugged in voltage test red wire is 12.9 volts brown wire 12.5

is there any other fuses other than rectangle box on 1988 fj1200

could it be alternator voltage regulator should I get this

https://www.rpmracingca.com/products.asp?cat=39&filter=rectifier

[Pat Conlon]

See page 235 of the Clymer manual
See 8-30 in the Haynes

Also read this: http://www.fjowners.com/index.php?topic=18995.0

I am not a fan of the internal VR.
The more you mount the VR further away from the engine heat and vibration, the better, IMHO.

[rollinghelmet]

In this post

http://www.fjowners.com/index.php?topic=18995.0

It says

Inspect the rotor resistance between the slip rings which should be 3.3-4.0 Ohms

Where am I measuring, engine running or not, is it the 2 screws that hold the voltage regulator on the alternator

What are the slip rings

[Pat Conlon]

Sorry, I thought the post was clear.

"TECHNICAL ISSUE DETAILS"
"This Yamaha model uses a Nippon-Denso car-type alternator that is mounted behind the cylinder block. Inside this alternator there is a field rotor with copper slip rings on which carbon brushes run. Around the rotor you will find the stator and in the front of the housing are the built in rectifier bridge and the electronic voltage regulator."

The rotor and stator are components of the alternator. The rotor spins. The stator is field of wires that surrounds the rotor. The brushes contact the spinning rotor on what are called slip rings. The slip rings are on the rotor.
Think of the slip rings like a commutator on an armature, it's what the brushes ride on.

You disassemble the alternator to get access to these components.

Also....Sorry to say, but your Haynes manual is of little to no help in bench testing your alternator.

In the Clymer manual, pages 236 and 237 outline the test procedures for the rectifier and stator coils.

Robert, do you have anything from the GFSM that can help this bloke?

[rollinghelmet]

I can not get any ohms reading between the slip rings with the brush assembly off

[Pat Conlon]

1) Remove and disassemble the alternator

2) Visually inspect rotor shaft, slip rings and windings. Look for electrical shorts that appear as burnt black streaks on the windings. Scored rings or a bent rotor shaft indicates that the rotor needs to be replaced. No further testing is necessary.

3) Connect one probe of the ohmmeter to a slip ring and the other to the rotor shaft. The resistance should be infinite; a low reading indicates that the rotor may be grounding out and needs to be replaced.

4) Connect both the probes of the ohmmeter to the slip rings to test for shorts or open circuits. If the reading is below the specified resistance shown in the manual (between 3.3 to 4 ohms), there is a short. A reading above the resistance indicates an open circuit.

Report back....Let us know what you find.

This sounds like a hassle, but I have learned (the hard way) that blindly throwing new parts at an electrical problem is a waste of money.

Don't get discouraged....

Pat

[rollinghelmet]

Urban_Legend  suggested trying a xjr 1300 alternator
got a second hand one off ebay $120
went for long ride today and all good