I'm busy removing the generator cover on the left hand side of the engine and noticed some oil dripping out. Not much, which leads me to think it could have seeped out through an oil seal. It certainly is not as much as there should be in the engine. I have not drained the engine oil, btw.

So, should the oil be drained before doing this? I wouldn't have thought so. The alternator doesn't run in oil.

Any thoughts?

it aint the sump but there is oil there.

Why are you removing it (being nosy...  )

There is a little oil behind it, in fact if you put it on the side stand you'd get more, I would center stand it or even lean it on the other side. Drain the oil if you are changing it anyway, but otherwise its normal to get some oil from that cover. Nothing is amiss.
Cool.
Buddha.

Thanks Srinath. That makes sense. I've removed the cover and there wasn't much oil.

Oh, btw, you might remember that we had a debate about the number of magnet poles in the alternator rotor some months ago. There are 12 poles, but only six magnets. Each magnet is divided into a North and South pole. If you look carefully, there is even some sort of dividing line - gray in my case. I used a loose magnet to verify the number of poles. (Not alternator magnet). Six North and six South poles.


@herennow: No, thankfully it's not noisy. Doing some cosmetic touch-ups on the engine covers. 

That design of alternator I guess while adequate isn't the most efficient. However I wholly prefer the permanent magnet style of the GS over the electromagnet with the brushes and this and that, not to mention those stator coils are also more fragile.
Cool.
Buddha.

Quote from: The Buddha on January 29, 2021, 12:05:31 PM
That design of alternator I guess while adequate isn't the most efficient.

The advantages of a three phase permanent magnet alternator is low voltage ripple and high efficiency. What type would you say is more efficient?

Quote from: SK Racing on January 29, 2021, 12:58:03 PM

Quote from: The Buddha on January 29, 2021, 12:05:31 PM
That design of alternator I guess while adequate isn't the most efficient.

The advantages of a three phase permanent magnet alternator is low voltage ripple and high efficiency. What type would you say is more efficient?

PM may be more efficient, but the control is better when you can vary field strength. (When the regulator controls the field voltage and current).

Its not all about electrical efficiencies. Think like a design engineer would.......... Its a motorcycle so space, weight and simplicity are the main considerations.

Small motorcycles use PM alternators because they are simple, compact, lightweight and maintenance free. They are easy to locate on the end of the crank and therefore don't need separate drive arrangements, the rotor also acts as a flywheel and they don't need to be large and have high output capacities because small motorcycles simply don't need large amounts of power.

I agree 100% with that, Sledge. But after having owned a GS500 for about four years, I think the charging system is adequate. Well, so long as it's in good condition - like mine still is.

Reason why I questioned Buddha's statement about it not being the most efficient, is that I know PM alternators are quite efficient. I design and build three phase generators and motors (as a hobby) to be used as wind generators and drone generators, and it's the best (most efficient) technology out there for that purpose.

Edit: I do think the R/R can be better though, because it can't be efficient if it gets hot. Mosfet regulators are a much better choice and I'm thinking to upgrade mine to Mosfet at the first sign of trouble.

Of course its adequate, its all it needs to be and lets not forget the bike and consequently its tech` is now over 30 years old.

Things move on and the GS5 wasn't exactly cutting edge even back then. Upgrading is a good thing in the main but the purists amongst us might disagree 

I was working on a bobbin with neodymium magnets bolted to it for a different bike. Going from an electromagnet to a bunch of neo's. More poles, more magnetic lines of force etc.
In fact I am also thinking I could build a speaker with that design that would really rip. Neo's can be made in ways and polarization you cant make a conventional magnet. You can make a tube with north on the inside and south on the outside. Make 2 of those 3" od and 3.125" id and put em with a voice coil in the middle, and say hello to 1000 db per watt.
BTW Dynaudio made a few of these in the early 90's and those things are so outrageously loud and clean and really they were no where near as insane as my description. A very mild n20-25 with sloppy ass VC gap and still rip.

Anyway, when the GS was made no neo's were available, in fact its got the best option for 1989 after which they never touched it, which IMHO was wise, cos anything they touched, they frucked up. Really GS doesn't have charging problems. It has magnet disintegrating problems. AKA quality control not design flaw.

I also suspect some of the magnets disintegrating are due to people ignoring the starter clutch hammering away, or a crash that was just hard enough to bend the case but not enough to split it. I know I did the former and I know of a few more too that did that. And Tarzanboy inherited the "lightly crashed and rotor hit stator" bike that ate 3 stators before its previous owner figured it out and fixed it.

Cool.
Buddha.

Get a dozen of these -
https://www.magnet4less.com/pair-of-high-temp-neodymium-magnets-1-od-x-3-4-id-x-3-4-90-deg-arc-n42sh
You can get them with bolt holes too. Then drill and tap your rotor and bolt em all and glue them too for good measure.

Congrads, you've replaced 6 N5's with 12 N42's. Then at idle our bike can light up your whole house.

Cool.
Buddha.

Quote from: The Buddha on January 30, 2021, 09:42:26 AM
I was working on a bobbin with neodymium magnets bolted to it for a different bike. Going from an electromagnet to a bunch of neo's. More poles, more magnetic lines of force etc.

It's not as simple as that. You can't just use an arbitrary number of magnets. The number of magnet poles need to match the original design or it may not work properly.  In motor/alternator design we have to use the correct winding diagram for the number of poles and stator teeth (we call the latter "slots").

There is a neat winding diagram calculator here: bavaria-direct.co.za/scheme/calculator

If you enter 18 slots and 12 poles in 2 layers Delta, you'll get the winding scheme for the GS500 stator.

Yea yea all that sciency stuff is all cool. But there's always the option of removing those poles by trial and error. I didn't have plans to do that on a GS, but that other one had too many parts NLA. Now it looks like they are available again so - meeeh lets see when I actually pick up a wrench ...
Cool.
Buddha.