GT380 Alternator Rotor Removal

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miked914
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Suzuki 2-Strokes: GT380

Re: GT380 Alternator Rotor Removal

Post by miked914 »

I grounded the R/R to the Black/White main ground off the alternator loom. It is showing ground but not sure if its OK to use that?

I get ZERO volts at the green wire either at the alternator body or at the other end of the wire. Continuity is good so no break in the copper.
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jabcb
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

To recap, with the bike turned on & not running, voltage at the R/R are:
1) black wire: 0V — this is correct because its the ground wire
2) red wire: 12.8V — this is correct because it connects directly to the battery
3) green wire: 0V — this is wrong
4) orange wire: 0V — this is wrong
5) 3 yellow wires — AC output from alternator, no need to check

The orange wire is the main power wire leading from the ignition switch to everything.
The orange wire sends power to the R/R, which then sends power to the alternator rotor via the green wire.

With the bike on but not running, the orange wire at the R/R should have close to 12.8V.
So this is your problem. (There might be another problem that might show up after you fix this.)
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
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Alan H
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

Remember that if either the ignition, or right bar kill switch is off, then there will be no power to the orange wire, therefore no power to the rotor via the regulator.
Main problem with charging is bad connections between battery and rotor via fuse, ignition, kill, lots of connections worn rotor brushes and earth.
Without the rotor working, the generator CANNOT work.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
miked914
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

Re-reading this I may not have been totally clear.

Power INTO the Orange wire on the R/R is 12.8
Power INTO the Green wire on the R/R is 0
Black wire is 0

When the RR is connected with battery power on, I'm getting 0 volts at the alternator brushes (no change when I have my handlebar switch on, which is only used to allow power to the coils)
miked914
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

By INTO the RR I mean the 3-prong OEM connector from the wiring loom (mine has 1 Green, 1 Black and 1 White/yellow wire). That connection is where I'm getting 0 at Green, 12.8 at the Yellow/White and 0 Black.

That 3 prong loom plugs into the matching connector for the RR--which has Orange(mates to the Yellow/White getting 12.8 volts)
Green mates to Green--0 Volts
Black to Black--0 Volts.

Should my Green wire be showing 12 volts at that connection? or does it get the voltage AFTER it leaves the RR?
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jabcb
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

If the R/R is getting 12.8V via the orange wire & the black wire is properly grounded, then you should have voltage on the green wire.
So either the R/R is the wrong unit for the GT380, or its defective.

Do you have a link to the R/R's eBay listing?
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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Alan H
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

miked914 wrote:Re-reading this I may not have been totally clear.

Power INTO the Orange wire on the R/R is 12.8 Correct. It's the switched live from the kill switch on the right handlebar.
Power INTO the Green wire on the R/R is 0 Correct. It should come OUT of the regulator. This will only happen when it's plugged in.
Black wire is 0 Correct. It's earth.

When the RR is connected with battery power on, I'm getting 0 volts at the alternator brushes (no change when I have my handlebar switch on, which is only used to allow power to the coils) AND THE REGULATOR
If the regulator was powered whenever the ignition was on and the engine not running, the battery would flatten very quickly.
Power comes OUT of the regulator to the rotor, so you'll only see voltage at the rotor when the regulator is plugged in. Disconnect the green wire to the rotor and test that to earth with your voltmeter. That'll tell you what is really going to the rotor.

Other threads on this subject are;
http://www.kettleclinic.co.uk/kcforum/v ... =11&t=9982&" onclick="window.open(this.href);return false;
http://www.kettleclinic.co.uk/kcforum/v ... =16&t=9768&" onclick="window.open(this.href);return false;
http://www.kettleclinic.co.uk/kcforum/v ... =16&t=7811&" onclick="window.open(this.href);return false;
I suppose I ought to condense them into a single topic and have it 'stickied'.........
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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jabcb
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

Looking at the wiring diagrams in: viewtopic.php?f=29&t=4743&start=0

orange wire - hot from ignition switch
orange/white wire - hot from engine kill switch

On the 1977 GT380B/GT550B/GT750 the voltage regulator is powered by the orange/white wire.
On the 1972 GT380J/GT550J/GT750J the voltage regulator is powered by the orange wire.

So on all model years, if the R/R is connected, the ignition is on, the kill switch is on & the engine is not running, then the voltage regulator is being powered.
At a minimum, the rotor has around the resistance of an ignition coil, so its not using that much power.

I currently suspect that the Chinese R/R is either defective or its the wrong R/R.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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Alan H
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

jabcb wrote:Looking at the wiring diagrams in: viewtopic.php?f=29&t=4743&start=0

orange wire - hot from ignition switch
orange/white wire - hot from engine kill switch

On the 1977 GT380B/GT550B/GT750 the voltage regulator is powered by the orange/white wire.
On the 1972 GT380J/GT550J/GT750J the voltage regulator is powered by the orange wire.

So on all model years, if the R/R is connected, the ignition is on, the kill switch is on & the engine is not running, then the voltage regulator is being powered.
At a minimum, the rotor has around the resistance of an ignition coil, so its not using that much power.

I currently suspect that the Chinese R/R is either defective or its the wrong R/R.
I wasn't sure what model it was, but they all run off a switched live. He does say switched live from the kill switch anyway.
The coils are between 3 and 6 ohms each and the rotor is between 2 and 5 ohms. So if you think that only one coil at a time is charging, plus the rotor, and we give then both midway ohmic readings, we have 3.5 + 4.5 ohms (in parallel) to make 1.96 ohms (call it 2 for easiness). Current is calculated by dividing volts by resistance so 12.8/2 = 6.4 amps. Depending on what battery you have 10/11 amp hour you're looking at a fairly short time to completely discharge the battery as the voltage falls during discharge. It's like leaving the lights on.
Put an ammeter in circuit between battery earth terminal and the wire you take off to see. Most decent testers will do 10 amps. The ignition system takes a helluva whack and so does the rotor, but the alternator puts it back quickly.
I keep offering a copy of the early service manual to anyone who wants one. It's for all models up to about 1973, but later models are still relevant in lots of ways, especially electrical.
PM me for a copy FOC.
The RR could be faulty, but check connections and brushes first.
Take off the green from the first brush and see what voltage you get on it (12.8 ish), then check each brush for length and spring tension. With second brush lifted (or a card under it so it doesn't touch the rotor)and green wire reconnected, see what voltage you get to the second stator ring - should be slightly less than the green wire. This proves 1st brush and rotor. Disconnect the earth from the second brush and drop the brush onto the stator - test on the terminal where you just removed the wire - should be just below the second ring test. That proves the second brush.
Reconnect the earth wire or terminal. But it has to be methodical.
Trust me, I've done this several times and worked in the trade a long time.
Charging is one of the main issues with these bikes, and 90% of the time it's a bad contact or worn brushes. 10% dirty contacts on the regulator or rarely the rotor.
They were never expected to last over 40 years!
Think of how stupid the average person is, then realise that half of them are more stupid than that.
miked914
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

Here is the unit I have

http://www.electrosport.com/regulatorre ... 50750.html" onclick="window.open(this.href);return false;

And to recap, I am not getting any voltage at the green wire or at the brushes
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Alan H
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

On the original wiring there are three plugs. One smaller one from the regulator (next to the start solenoid), 1 6 pin to the rectifier (next to and slightly below the solenoid, and one 6 pin from the generator. The bigger sockets are partially interconnected and the small one comes just from the harness.
I know you will have checked, but are you certain that the new large plug is in the correct socket?
Check that the wires coming into the rear of the socket are the same as the ones in the plug going into it - and in the same order. I can't see the colours of the wires to the small plug in the suppliers' picture.
I would suggest that the new unit has the black wire put to one of the mounting bolts and also that you run another wire from battery negative to the same mounting stud.
I actually run a wire from battery earth to just in front of the battery (frame bolt) then to solenoid mount, indicator relay mount, rectifier mount and frame to ensure that everything is well earthed after having the frame(s) powder coated. If it's done neatly, it looks OEM!
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

Interesting. I just bought an ElectroSport ESR770 for my GT380 project bike. I’m not quite ready to install it & was planning on doing it in a week or two. I’ll take a closer look at it in the next few days.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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jabcb
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

Had a little free time so I did a brief check with my ESR770.

Connected only two wires: (1) black directly to the battery & (2) orange to the bike’s voltage regulator connector.
Got the same voltage on the R/R orange & green wires.

Connected three wires: (1) black directly to the battery, (2) orange to the bike’s voltage regulator connector, & (3) green to the bike’s voltage regulator connector.
Got a slight voltage drop across the R/R. Voltage at the orange wire was slightly higher than at the green wire.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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Alan H
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

I'd like to see some instructions for it to see if I can make any sense of what it actually is!
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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jabcb
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

It looks just like the picture mike914’s link.
The instructions are here: http://www.electrosport.com/technical-r ... ctions.pdf

The voltage regulator connector has two wires: orange & green.
The rectifier connector has 4 wires: red & 3 yellows.
It has a separate black wire for ground.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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