reg/rect fubar?

got my hands on a cheap multimeter this morn. to start with, my 4month old new battery which wouldnt start the bike yesterday reads 12 volts. my old 'apparently' dud battery(which has been sitting up for 4months) reads 12.7 and started the bike yesterday 1st time.

*the following test was gotten off an auzzie sv site:

Connect the meter on the 20 volt DC range to the battery in the bike.

1. With the ignition ‘off’, the battery should show about 12.8 volts after 1 hour. (Below 12.5 volts and it’s not charged properly, two or more volts lower and it’s probably dead).

2. When you turn the ignition ‘on’ the voltage should drop back to about 12.0 volts. (Below 11.5 volts it’s very sick)

3. While you press the starter button it should drop back to just over 10 volts. Below this the battery (or the starter motor) is sick.

4. After the engine starts (at idle) it should rise to over 13.0 volts (at 12.0 – 13.0 volts your regulator is suspect)

5. Turn the headlights onto High Beam and rev the bike to 5,000 Rpm. The reading should be over 14.0 volts. If it is below this, the regulator is stuffed. Don't kid yourself at this point, low voltage = dead reg.
(Note: the ‘official’ Suzuki spec says 13.5 – 15.0 volts, I believe anything below 14.0 volts isn’t enough and indicates a blown diode in the regulator.)

*my test was done with the 12.7 v old battery:

1. - 12.7

2. - 12.5

3. - 9 ish (jumpy)

4. - 13.4 and rising slowly

5. - 12.6 !!

once i turned the bike off it returned to 13.3 and began to drop slowly down into the 12 range. i know it says above but am i right in sayin my reg/rect is fcucked??

[Biker Biggles]

Are you sure about that 1.6 reading?Something very wrong there,but maybe a wiring problem somehere?
BTW it seems both your batteries work and just need charging up.Have you got a trickle charger?

[Biker Biggles]

Oh and to test the alternator you start the bike,and check the output from the three yellow wires that come out of the alt to the reg.Test each wire to each other wire----1-2 2-3 1-3 and look for similar outputs on each measure.I got about 65 volts AC IIRC.If you get similar your alternator is putting out correctly.

Originally Posted by Biker Biggles

Are you sure about that 1.6 reading?Something very wrong there,but maybe a wiring problem somehere?
BTW it seems both your batteries work and just need charging up.Have you got a trickle charger?

yep tried step 5 three times. havent got a charger, but the old battery(12.7v) one was brought to a shop and charged, but they said it was dropping and i needed a new one(4months ago). yet when i pulled it out from storage and put it in the bike yesterday it started it 1st time and twice more and then this morning for the test. dya reckon this 'old' battery is actually ok?

im a fool. that 1.6 reading was wrong. not enough hands when ya need them! did it all again and it should really read 12.6. will edit it now. suppose its still fubar though.

[Biker Biggles]

Now test the alternator output as I posted above.That may well be your problem.

Originally Posted by Biker Biggles

Now test the alternator output as I posted above.That may well be your problem.

i dont know how first time iv ever done anything electrical. also wheres the alternator?

[Biker Biggles]

There are three yellow wires that come out of the engine casing left of rear cylinder block and go to the reg via a block connector.The reg is on right side under the seat cowling.These wires will be covered in black loom tape,but they are yellow.If you unclip the block connector you can test them as descibed above with the multimeter set to AC and appropriate range.
Better still do a search on here for a thread by Nadine Bienne on the same issue.There is a comprehensive guide with pics to demonstrate exactly how to do this and repair the bike as needed.

Originally Posted by Biker Biggles

There are three yellow wires that come out of the engine casing left of rear cylinder block and go to the reg via a block connector.The reg is on right side under the seat cowling.These wires will be covered in black loom tape,but they are yellow.If you unclip the block connector you can test them as descibed above with the multimeter set to AC and appropriate range.
Better still do a search on here for a thread by Nadine Bienne on the same issue.There is a comprehensive guide with pics to demonstrate exactly how to do this and repair the bike as needed.

thanks Biggles. exactly what i needed. 25 pages of reading though! think i have it all sussed. will give the alternator a bash in the morn

update: here are all old and new figures:

*my test was done with the 12.7 v old battery:

1. - ignition off - 12.7

2. - ignition on - 12.5

3. - pressing starter button - 9 ish (jumpy)

4. - engine idleing - 13.4 and rising slowly

5. - lights on high and rev to 5,000rpm - 12.6

went for a spin last night and bike started 4 times on the button. didnt drive with lights on for 1st half.

this morning the battery is reading 12.7. ignition on is 12.65 and dropping very very slowly.

resistance test for alternator. done on first relevant connector block from engine(100%sure referencing nadine's thread). all other related connectors were unplugged.

3 yellow wires 'individual to earth' test (i used battery)
- infinity with all combinations.

3 yellow wires 'combination to each other' test
- 1.2 for every combination

3 yellow wires 'combination to each other' voltage test.
bike was started and ran at 5,000 rpm
- 90 for each combination.

thats it i think. now how do i interpret these figures? i imagine its still alternator ok, reg/rect ****ed.