Reg/Rec and Generator fault diagnosis (and battery test)---
Posted: Thu Aug 26, 2010 2:28 pmThe generator produces electricity (of the AC type- the same as is in your house) to recharge the battery on your bike and run the engine and electrical system when you’re on the move. The Regulator/Rectifier (Reg/Rec) takes the AC power from the generator coils and 1) Rectifies it to DC current which can be used by the bikes electrical components and; 2) Regulates it to a the right voltage.
If the bike isn’t charging properly or if strange things are happening with the electrics (blown bulbs and fuses all of a sudden, unexpected flat battery etc etc). Try these tests in order BEFORE riding the bike if at all possible. The first test, checks the generator coils and the second, short test, checks the reg/rec. Treat the whole thing as a set routine. You only need a multimeter and an assistant and it’s easy, only taking a couple of minutes once you’ve got the seat and tail fairing off—
TEST 1- GENERATOR COILS
Locate and unplug the reg/rec. The carb models have one plug- the FI's have 2 plugs.
Set your multimeter to 200v AC range (AC is not the norm with 12V systems, but it is what you need for this test)
Looking at the reg/rec plug and you will see three yellow wires (for the sake of calling them something- A, B & C will do nicely) there’s no visible difference between them and don’t worry about that.
Start the bike and get someone to hold the revs at around 3000 rpm. With the engine running at that speed- test the voltage across wire A & B and write down the reading, the do the same across wires A & C and lastly, wires B & C. All three voltages you have written down should be similar (say within 1 or 2 Volts of each other) and all should read around 24-27V for carb'd machines or 40-60V for FI machines.
If one of the voltages is outside the above parameters, or the voltages are considerably outside the 24-27V (carb) or 40-60V (FI) range then the generator coils have failed and will have to be replaced.
If the voltages are all within the parameters above, then the reg/rec has failed and will have to be replaced.
TEST 2- REGULATOR/RECTIFIER
It’s possible that if the reg/rec has failed, it has taken the generator coils with it. If it has, replace the generator coils first and when they’re replaced, set the multimeter to the 20V DC setting and put the test probes across the battery terminals (Red to live, Black to earth). Start the engine. Initially, with the starter motor turning the crank there will be a drop in voltage (expect 10.5-11V), but when the engine catches, you should see the voltage reading rise immediately and continue to rise and fall when the engine is gently revved and released.
If the voltage doesn’t move or if the reading drops slightly- CUT THE ENGINE immediately and order a new reg/rec, because the original has failed. Don’t run the engine a second longer than you have to and bearing in mind the test reveals results immediately the engine fires up, it should be less than 10 seconds.
Finally, and assuming the voltage is flowing as expected, flick the headlight and main beam on and rev to 5000 RPM. In a perfect world, you'll see figures in the mid 14's Volts. As a personal comment, my first 'bird ('96 build carb) ran at 14.9 Volts and it didn't bother the reg/rec or anything else throughout the life of the bike.
And that’s it- how to check for failed generator coils and reg/rec in a nutshell.
TEST 3- BATTERY
Well... Look, you're standing there with the seat off and the multimeter to hand, so you might as well check the battery voltages (static and deep). If you do this, you've checked and cleared the entire charging system. Before doing this however, let me say that these tests are simple and basic. I haven't accounted for testing in extreme temperatures (which can make a difference to readings) so if you're doing this in winter at zero degrees let me know and I'll try find the appropriate figures for you.
First test, is the static charge or to put it another way, what voltage your battery is holding at the time of the test itself. First make sure the battery is fully charged then set the multimeter to 20V DC and place the probes across the battery terminals (red-pos and black -neg). In a healthy battery the reading should be over 12.7V.
Second test is a load test. This is a tad fiddly, but well worth it because test 1 alone means very little. What you really need to know is what your battery can push out and for how long. So the test...
1. Again with battery fully charged, disconnect the ignition. On carb models remove the earth or live wire from each of the coils and on FI models, removing the ECU fuse should do it (I think, because I don't own one). The purpose is to be able to spin the engine on the starter button, without the engine firing up.
2. With the ignition disabled, turn on the ignition switch and turn the headlight on for three minutes. This will scrub off what's known as surface charge.
3. After three minutes, set the multimeter to 20V DC and place the probes across the terminals as with test 1 above. Then push the start button 30 seconds whilst closely watching the multimeter reading. The voltage should not drop below 9.6V at any time throughout the 30 seconds. A good, strong healthy battery won't drop below 10.5V during that test, so between those values and you're on the money.
It might be worth mentioning that specific battery load testers can be bought. Instead of disabling the ignition, the device has a resistor built in, that simulates the load required to stress the battery. All you do is connect the device across the terminals and look at the read-out. Not tempted meself, but worth a mention in passing.
Anecdotally (but worth a mention anyway) about batteries- I recently blew my reg/rec on a run out. The consistent power surge involved evaporated most if not all of the electrolyte away. Static testing of the battery produced a reading of 12.4V. Load testing was zero, barely enough to keep the dash clock running on time.
Hope it helps
Mick
If the bike isn’t charging properly or if strange things are happening with the electrics (blown bulbs and fuses all of a sudden, unexpected flat battery etc etc). Try these tests in order BEFORE riding the bike if at all possible. The first test, checks the generator coils and the second, short test, checks the reg/rec. Treat the whole thing as a set routine. You only need a multimeter and an assistant and it’s easy, only taking a couple of minutes once you’ve got the seat and tail fairing off—
TEST 1- GENERATOR COILS
Locate and unplug the reg/rec. The carb models have one plug- the FI's have 2 plugs.
Set your multimeter to 200v AC range (AC is not the norm with 12V systems, but it is what you need for this test)
Looking at the reg/rec plug and you will see three yellow wires (for the sake of calling them something- A, B & C will do nicely) there’s no visible difference between them and don’t worry about that.
Start the bike and get someone to hold the revs at around 3000 rpm. With the engine running at that speed- test the voltage across wire A & B and write down the reading, the do the same across wires A & C and lastly, wires B & C. All three voltages you have written down should be similar (say within 1 or 2 Volts of each other) and all should read around 24-27V for carb'd machines or 40-60V for FI machines.
If one of the voltages is outside the above parameters, or the voltages are considerably outside the 24-27V (carb) or 40-60V (FI) range then the generator coils have failed and will have to be replaced.
If the voltages are all within the parameters above, then the reg/rec has failed and will have to be replaced.
TEST 2- REGULATOR/RECTIFIER
It’s possible that if the reg/rec has failed, it has taken the generator coils with it. If it has, replace the generator coils first and when they’re replaced, set the multimeter to the 20V DC setting and put the test probes across the battery terminals (Red to live, Black to earth). Start the engine. Initially, with the starter motor turning the crank there will be a drop in voltage (expect 10.5-11V), but when the engine catches, you should see the voltage reading rise immediately and continue to rise and fall when the engine is gently revved and released.
If the voltage doesn’t move or if the reading drops slightly- CUT THE ENGINE immediately and order a new reg/rec, because the original has failed. Don’t run the engine a second longer than you have to and bearing in mind the test reveals results immediately the engine fires up, it should be less than 10 seconds.
Finally, and assuming the voltage is flowing as expected, flick the headlight and main beam on and rev to 5000 RPM. In a perfect world, you'll see figures in the mid 14's Volts. As a personal comment, my first 'bird ('96 build carb) ran at 14.9 Volts and it didn't bother the reg/rec or anything else throughout the life of the bike.
And that’s it- how to check for failed generator coils and reg/rec in a nutshell.
TEST 3- BATTERY
Well... Look, you're standing there with the seat off and the multimeter to hand, so you might as well check the battery voltages (static and deep). If you do this, you've checked and cleared the entire charging system. Before doing this however, let me say that these tests are simple and basic. I haven't accounted for testing in extreme temperatures (which can make a difference to readings) so if you're doing this in winter at zero degrees let me know and I'll try find the appropriate figures for you.
First test, is the static charge or to put it another way, what voltage your battery is holding at the time of the test itself. First make sure the battery is fully charged then set the multimeter to 20V DC and place the probes across the battery terminals (red-pos and black -neg). In a healthy battery the reading should be over 12.7V.
Second test is a load test. This is a tad fiddly, but well worth it because test 1 alone means very little. What you really need to know is what your battery can push out and for how long. So the test...
1. Again with battery fully charged, disconnect the ignition. On carb models remove the earth or live wire from each of the coils and on FI models, removing the ECU fuse should do it (I think, because I don't own one). The purpose is to be able to spin the engine on the starter button, without the engine firing up.
2. With the ignition disabled, turn on the ignition switch and turn the headlight on for three minutes. This will scrub off what's known as surface charge.
3. After three minutes, set the multimeter to 20V DC and place the probes across the terminals as with test 1 above. Then push the start button 30 seconds whilst closely watching the multimeter reading. The voltage should not drop below 9.6V at any time throughout the 30 seconds. A good, strong healthy battery won't drop below 10.5V during that test, so between those values and you're on the money.
It might be worth mentioning that specific battery load testers can be bought. Instead of disabling the ignition, the device has a resistor built in, that simulates the load required to stress the battery. All you do is connect the device across the terminals and look at the read-out. Not tempted meself, but worth a mention in passing.
Anecdotally (but worth a mention anyway) about batteries- I recently blew my reg/rec on a run out. The consistent power surge involved evaporated most if not all of the electrolyte away. Static testing of the battery produced a reading of 12.4V. Load testing was zero, barely enough to keep the dash clock running on time.
Hope it helps
Mick
and if it's nasty... bollox 
)
site and came across a flow chart for analysing problems with the battery/ generator/ reg-rec. There they gave the AC voltage range from the yellows ( or white as they are in the States ) from 40 to 60 V. Don't know for certain, but perhaps that is the result of an uprated genny for the FI over the carb model.
handle ( inside the seat cowl ) where there is an opening for your hand. So in theory, it should get more air for heat dissipation.
... you change your regrec quite often then... 
