1982 GS550 stator problem

[Isetta]

First of all. Apologies, I put this in the general discussion area but have now realised there is a section for electrical so I have re-posted it here.

a) Alternator not charging. Ohms between the wires reads fine and matches the readings from my other gs550 which charges fine. Also no continuity to the stator base. Measuring the ac voltage between each two wires only gets to 6 volts at 3000rpm but on my other working bike it gets to 50 volts at 3000rpm . So I removed stator. It’s very black. I know from reading stuff on the internet it is common for them to bake and fail. But from a scientific point of view what has actually gone wrong ? If the ohms / Continuity tests still read right. I accept that I need to buy one but I just want to understand why it doesn’t work if ohm / continuity testing seems fine. I don’t think it’s original stator as it has three grey wires. Photo of stator attached.

b) Another query, the rotor has 12 magnets in it. As far as I can see the 18 pole stator (like mine) uses a 12 magnet rotor and the 12 pole stator uses an eight magnet rotor. Is that right?

c) Another query in my mind. Can the rectifier/regulator combined unit (quality/condition) affect the lifespan of the stator?

Please let me know , thanks.

 

[Nessism]

Your bike should have an 18 pole stator. I'm not sure how many magnets on the rotor that equates too, though.

You, obviously, need a new stator, and it's highly recommended to purchase a "series" type R/R, because they help protect your stator from return current overheat damage. The Shindengen SH775 is the most popular choice in series type R/R's. Beware, though, because there are a LOT of fakes on the market. It's best to look for a used unit on ebay or similar, and verify that "SH775" is printed on the top fin before purchase. Also, bypass the stator look routing thought he hand control. That can lead to melted wires in the harness.

Good luck

 

[Rich82GS750TZ]

Ed just wrote everything I was going to.

 

[Isetta]

Hi Nessism, thanks for reply - so the bit about the hand control. I am aware that one of the three stator wires only connects to the regulator when the headlamp is switched on. I know some USA bikes have the headlamp fixed to on, but United Kingdom bikes had a headlamp switch on right hand switch unit. So when you say bypass that bit, are you just saying that is OK to do on USA bikes where the headlamp stays on or are you saying I should do that on a UK bike because the regulator can cope with all three stator wires connected even when the headlamp is off? Please could you clarify that bit, Thanks

 

[Nessism]

Hi Nessism, thanks for reply - so the bit about the hand control. I am aware that one of the three stator wires only connects to the regulator when the headlamp is switched on. I know some USA bikes have the headlamp fixed to on, but United Kingdom bikes had a headlamp switch on right hand switch unit. So when you say bypass that bit, are you just saying that is OK to do on USA bikes where the headlamp stays on or are you saying I should do that on a UK bike because the regulator can cope with all three stator wires connected even when the headlamp is off? Please could you clarify that bit, Thanks

I'd do the bypass regardless. Reason being, as the electrical harness connectors develop resistance, that means more current and heat through the wires, and it's very common for the stator loop wires to melt and take out a section of the harness with it. Besides, if you get a SH775, that eliminates the need for the loop anyway.

BTW, I've got a couple of spare SH775s if you can't find one. Sadly though, shipping from the US to UK can be expensive.

 

[craz1]

When I was correcting my wire harness I noted that bypass and thought what the hell. Why would they bring one phase up to a plug by the headstock and then back down. That cant be good. So now I have the reg/rec as mentioned with all 3 leads from the alternator going directly to the reg/rec. Defiantly do the bypass.

 

[Isetta]

Thanks for the advice. I will first get a stator and check I am getting the correct ac volts from the three stator wires, once that bits sorted I can move forward with the bypass wiring and regulator/rectifier

 

[Isetta]

Re SH775 regulator. Thanks for the offer. International shipping is expensive and when stuff arrives in uk the post office send a card saying how much import duty I have to pay AND they add an additional service fee for handling the import duty. I then have to pay those before they deliver the package. In uk I can get a 2nd hand sh232 from a Honda cb250n super dream for generally about 40 US dollar equivalent. Stuff on internet suggests that unit is good for gs550. I have no idea what difference is between sh775 and sh232. Are people on this forum of the opinion that unit does the job fine?

 

[Nessism]

Re SH775 regulator. Thanks for the offer. International shipping is expensive and when stuff arrives in uk the post office send a card saying how much import duty I have to pay AND they add an additional service fee for handling the import duty. I then have to pay those before they deliver the package. In uk I can get a 2nd hand sh232 from a Honda cb250n super dream for generally about 40 US dollar equivalent. Stuff on internet suggests that unit is good for gs550. I have no idea what difference is between sh775 and sh232. Are people on this forum of the opinion that unit does the job fine?

SH232 is a shunt R/R. Cheap and reliable. Realize, though, any power produced by the generator that is not consumed by the bike, will be "shunted" back to the stator, where it's dissipated as heat. This heat then puts stress on the stator and can break down the insulation over time.

One possible option, to save money, is to look for a Kawasaki KZ stator that will fit your bike. KZ's don't make as much electrical power, thus there is less to shunt back to the stator. Their stator failure rate is far less than GS bikes, despite both using shunt R/R's from the factory. I've heard of people here using KZ stators, but I don't have much more to share other than to say it's been done before.

 

[tom203]

The SH-775 is worth hunting for……it spares the stator of useless heat. Try shops that sell/repair ATV’s. The bigger Polaris atv’s had the SH-775 starting about year 2000 or so……lots of these atv critters get wrecked and abused.
The 18 pole stator was matched with a 12 pole rotor…6 pairs of N/S magnets .
The 12 pole stator was matched with a 8 pole rotor …4 pairs of N/S magnets

 

[sacruickshank]

BTW, I've got a couple of spare SH775s if you can't find one. Sadly though, shipping from the US to UK can be expensive.

Jumping in on this, I may need one of those R/R from Ed/Nessism. The new battery on my '81 550T won't hold a charge and is now ~dead.. I haven't yet checked the stator or chased the wiring for a bad ground, but will try to get to that this weekend.

What did you have in mind for a price, shipped to 02052?

My other option on hand is a SH-238-12 from a Honda GL500. Looks good visually, but I don't know it's functional condition.

 

[Isetta]

An update on my stator. I decided to take a chance on a 2nd hand one on ebay which did not look black. 15 GBP (21 US Dollars) including delivery. Arrived today, fitted it, and it works.
It seems to be original suzuki part from the wiring colours. Comparing this to my dead one (which is not genuine suzuki going by three grey wires), the replacement one has gaps between the coils, the dead one does not, the gaps are filled with resin (or whatever it is they use). I wonder if that contributed to its demise in that it may hinder the dissipation of heat.

 

[Grimly]

An update on my stator. I decided to take a chance on a 2nd hand one on ebay which did not look black. 15 GBP (21 US Dollars) including delivery. Arrived today, fitted it, and it works.
It seems to be original suzuki part from the wiring colours. Comparing this to my dead one (which is not genuine suzuki going by three grey wires), the replacement one has gaps between the coils, the dead one does not, the gaps are filled with resin (or whatever it is they use). I wonder if that contributed to its demise in that it may hinder the dissipation of heat.

Bear in mind that if you use the shunt reg-rec, always have your headlight on.

 

[fastbysuzuki]

isetta if you require a sh775 I have on here in the uk I have tested it on my 850 it works fine pm me if you are interested or I have the Oem one?