1981 GS450 wiring Question

[Guest]

Hey all, new to the forums! I've recently decided to learn more about motorcycles and bought a non running gs450 (only electrical as far as i'm aware) with the goal of going from the basic knowledge on how an engine works to getting the bike running and eventually riding. But when I was looking over the wiring Diagram for my gs450, I noticed that one of the wires come out of the generator, goes through the lighting switch, and then goes into the Reg/Rectifier but the other two wires coming out of the generator go straight into the Reg/Rectifier. Anybody know what's the reason for this?

[Blue Falcon]

Yes... suzuki was retarded when they made that design. A lot of people remove that from the equation. Check out the "Stator Papers" and other from the bike cliff website and thegsresources.com main page. Will explain a lot.

[John Park]

Having one loop go to the switch was not retarded. In markets that wanted a headlight on/off switch, having one loop of the alternator disconnected along with the bulb reduced the load on the regulator having to get rid of the excess current.

If the headlight is non switchable, having an extra loop to nowhere and back is just heating the wiring harness and more things to go wrong. I guess Suzuki didn't like making two different wiring harnesses.

[posplayr]

Having one loop go to the switch was not retarded. In markets that wanted a headlight on/off switch, having one loop of the alternator disconnected along with the bulb reduced the load on the regulator having to get rid of the excess current.

If the headlight is non switchable, having an extra loop to nowhere and back is just heating the wiring harness and more things to go wrong. I guess Suzuki didn't like making two different wiring harnesses.

Thanks, that is much simpler answer than I could answer.

[Blue Falcon]

Having one loop go to the switch was not retarded. In markets that wanted a headlight on/off switch, having one loop of the alternator disconnected along with the bulb reduced the load on the regulator having to get rid of the excess current.

If the headlight is non switchable, having an extra loop to nowhere and back is just heating the wiring harness and more things to go wrong. I guess Suzuki didn't like making two different wiring harnesses.

No one gets what I was saying... nevermind... why did engineers have to be one-dimensional back in the 70's/80's in regards to the electrical system.... please don't answer my sarcastic comment meant purely for rhetoric.

[posplayr]

No one gets what I was saying... nevermind... why did engineers have to be one-dimensional back in the 70's/80's in regards to the electrical system.... please don't answer my sarcastic comment meant purely for rhetoric.

There are perfectly rational reasons for doing everything they did. Technically they may not have been optimal, but when considering cost they make plenty of sense. There was nothing really "retarded" as you characterize it.

[Blue Falcon]

There are perfectly rational reasons for doing everything they did. Technically they may not have been optimal, but when considering cost they make plenty of sense. There was nothing really "retarded" as you characterize it.

Retared - not today's definition, but much earlier. They had 2 phase ac with load sensing back then, they also had 3 phase had load sensing... the load determined the field flash and therefore only what was needed was made. When I was working on these.. .the control module fit in my hand...it was automatic.. and that was early 70's tech on power generation equipment. Cost effectiveness on a bike may have been different back then, but it was still available. Regardless of speed or load, output was regulated and was highly effective.

Not technically optimal is an understatement, even for 70's/80's design.

[roeme]

You have to take manufacturing into account, think assembly line and thousands of units produced.

Everything that you can leave unchanged between models...it adds up.

(That being said, we now know that the R/R mostly ain't up to par. Then again, Suzuki might not have envisioned a 30+yrs lifespan).

[posplayr]

Retared - not today's definition, but much earlier. They had 2 phase ac with load sensing back then, they also had 3 phase had load sensing... the load determined the field flash and therefore only what was needed was made. When I was working on these.. .the control module fit in my hand...it was automatic.. and that was early 70's tech on power generation equipment. Cost effectiveness on a bike may have been different back then, but it was still available. Regardless of speed or load, output was regulated and was highly effective.

Not technically optimal is an understatement, even for 70's/80's design.

Sounds like field controlled alternator that would generally require a slip ring/brushes.

The Shunt R/R is ubiquitous in the industry due to the low cost design of the SCR based designs. All manufacturers used it so it becomes the standard despite the flaws. I'm not defending the technical merits of a SHUNT R/R, but the headlamp loop was a bandaid to accommodate the SHUNT R/R. If there was a field controlled alternator the headlamp loop would have never appeared.

[Blue Falcon]

Sounds like field controlled alternator that would generally require a slip ring/brushes.

The Shunt R/R is ubiquitous in the industry due to the low cost design of the SCR based designs. All manufacturers used it so it becomes the standard despite the flaws. I'm not defending the technical merits of a SHUNT R/R, but the headlamp loop was a bandaid to accommodate the SHUNT R/R. If there was a field controlled alternator the headlamp loop would have never appeared.

even this small it could have been brushless. For the mass production, could have been one size fits all from 400-1100. Sometimes I wish o had a time machine.

[Gorminrider]

Hey all, new to the forums! I've recently decided to learn more about motorcycles and bought a non running gs450 (only electrical as far as i'm aware) with the goal of going from the basic knowledge on how an engine works to getting the bike running and eventually riding. But when I was looking over the wiring Diagram for my gs450, I noticed that one of the wires come out of the generator, goes through the lighting switch, and then goes into the Reg/Rectifier but the other two wires coming out of the generator go straight into the Reg/Rectifier. Anybody know what's the reason for this?

lots of good answers discussion above but the real question for you might be-"Can I turn my headlight off and on?" Many bikes began to lose the option as a safety feature per daytime running light. Suzuki left the loop in however. I had to fiddle with the switch to "reclaim" the on/off headlight switch on my 81

[John Park]

lots of good answers discussion above but the real question for you might be-"Can I turn my headlight off and on?" Many bikes began to lose the option as a safety feature per daytime running light. Suzuki left the loop in however. I had to fiddle with the switch to "reclaim" the on/off headlight switch on my 81

My worry was that the headlight would burn out and in daylight I couldn't tell; then, a few hundred miles later my stator/R/R would fry out. I took a piece of aluminum bent 90 degrees and attached it with the top headlight screw so I can see by reflection at a glance that it is still shining without having to put my hand in front. Sort of a reverse warning light. With a series regulator it probably isn't as big a problem, but if you've ever done the hand over the headlight routine this is nicer.

[Gorminrider]

^ good idea! I'll do that! Thanks JP. I'm more worried I'll forget to turn the headlight on, than about the stator ( I like starting the bike without headlight on-starts very well but someday there'll be that day when I need to clear a flooded motor or the like and a bit of extra capacity is nice)