GT380 Alternator Rotor Removal

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jabcb
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

Probably not, because you have two rotors that read ~6.5 ohms.

But if you have two early rotors that Suzuki had problems with, they might have gone bad in the same way.
Did you check your spare against the service bulletin to see if you have early of later rotors?

It might be easiest to figure out at this point if you post pics of how you’ve got it wired up.
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

What's the easiest way to post pics to this site? I'm never able to size them small enough to post.
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

I still have to do the AC test from the 3 stator wires--I'll try to get on that this evening.
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

You can’t post pics on this site. You post pics on a photo sharing site like flickr & then include links to those pics in your posts here.
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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Re: GT380 Alternator Rotor Removal

Post by miked914 »

Alright, I put a meter across all 3 of the yellow wires coming from the stator with the bike running at idle and then with some hearty revving.

Idle-- .5XX volts
Rev --1.5 - 1.8 volts
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

Do you mean that you connected the two meter probes to two of the yellow wires?
If you did, you should have gotten 20+ volts.
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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Re: GT380 Alternator Rotor Removal

Post by miked914 »

Yes sir, red probe to one yellow wire, then black to each of the other 2 (repeated for all wires).

So am I looking at bad stator, rotor or both?
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Re: GT380 Alternator Rotor Removal

Post by jabcb »

Should be able to figure out which part is bad with a few more checks. First I need to read through the entire topic when I have some time.
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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Re: GT380 Alternator Rotor Removal

Post by Craig380 »

miked914 wrote:Alright, I put a meter across all 3 of the yellow wires coming from the stator with the bike running at idle and then with some hearty revving.

Idle-- .5XX volts
Rev --1.5 - 1.8 volts
That was on the AC voltage setting on the meter, yes? The output from the stator is AC.

And you're getting battery voltage in the orange wire into the reg/rec, and the green wire out of the reg/rec?
1976 GT380 - wounded by me, and sold on
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

Correct--I was on the AC setting and used 2 meters to verify . Same numbers on both.

And when I checked for DC volts out of the RR, I put 1 lead on the ORANGE wire out of the RR (on DC setting) and the other lead on the GREEN wire at the Alternator (along with the brushes, slip rings, brush holder) and I'm getting battery voltage everywhere on the Alternator.
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

miked914 wrote:Correct--I was on the AC setting and used 2 meters to verify . Same numbers on both.

And when I checked for DC volts out of the RR, I put 1 lead on the ORANGE wire out of the RR (on DC setting) and the other lead on the GREEN wire at the Alternator (along with the brushes, slip rings, brush holder) and I'm getting battery voltage everywhere on the Alternator.
Testing like that, there should be 0 volts or very close.
You should only get battery voltage if you test between green and earth, or orange and earth.
Orange goes INTO the reg, not out. See my earlier posts.
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 »

Need to sort through some of the confusion…

With the key on & the engine kill switch on. And with the meter on DC & the black lead on the battery negative terminal.
1) the voltage with the meter red lead on the R/R orange wire
2) the voltage with the meter red lead on the R/R green wire
3) the voltage on one of the rotor slip rings
4) the voltage on the other rotor slip rings
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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Re: GT380 Alternator Rotor Removal

Post by sportston »

In answer to your original question. You kind of do need a special tool to remove it. But it isn't that special. You need a length of hardened steel about 7mm in diameter (a cut down allen key would work or maybe HSS drill bit) and your front engine mount bolt. I can't remember what the length of steel rod should be, sorry. You may have to experiment. DON'T DO WHAT I DID....I used a cut down 6mm bolt. The steel was too soft, iron alloyed with butter I think! It bent and splayed and was then stuck in the crank, while the rotor was still jammed solid. Eventually I managed to get it apart and remove the offending butter bolt but I was very lucky not to have damaged the thread in the crank!
After locking the engine, do the following;-
1. Remove bolt that holds rotor onto crankshaft.
2. Insert length of hard steel into hole.
3. Get front engine mount bolt and screw it into the rotor until it tightens against the hard length of steel.
4. Once tight, place socket over end of bolt and hit it sharply with a club hammer.
5. If it doesn't come loose, tighten bolt a little more and hit with hammer again.

Make sure you get the correct bolt! Of the three engine mount bolts, only one of them has an extended end that is designed to avoid thread damage when you use it in this fashion. Yes, Suzuki designed it this way. Clever, huh? And also, be sure to clean and grease the thread of bolt before insertion.

And DO NOT use a 2 or 3 leg puller on the rotor. Doing so would almost certainly damage the rotor.

By the way, if you find you need to replace your rotor, check carefully that any used replacement has no crack or damage to the top of it. They are easily cracked and many of the ones you find on ebay are so badly beaten up as to be useless.
Also check that your brushes are not badly worn and move freely up and down against their spring pressure and... ensure that the surface the brushes rub against is clean and undamaged. Meths and a rag will clean up the surface ok.
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Re: GT380 Alternator Rotor Removal

Post by miked914 »

Jab--

With the key on & the engine kill switch on. And with the meter on DC & the black lead on the battery negative terminal.(DONE)
1) the voltage with the meter red lead on the R/R orange wire--ZERO Volts
2) the voltage with the meter red lead on the R/R green wire--ZERO Volts
3) the voltage on one of the rotor slip rings--Zero Volts
4) the voltage on the other rotor slip rings-ZERO Volts.
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Re: GT380 Alternator Rotor Removal

Post by Alan H »

You should have battery voltage tp the RR orange. Ig nothing goes in, nothing can come out and if nothing is going to the rotor, then the alternator doesn't work.
With ignition and kill switch both on, the bike should start and there should be power to that orange wire. If not, tou have to find out why not.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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