New stator same as old stator?!

[J Paster]

I'm hoping someone out there has had this issue; it's starting to cost me wayyy too much money. I have a 78 GS1000E with 45k miles. I restored it last year and use it 2 - 3 times a week to commute to work. Recently, the battery died, so while I was replacing it, I stripped the bike to check and clean all the connectors. I also grabbed my trusty copy of The Stator Papers and went to work checking the charging system. Sure enough, my stator output checked out at about 45v AC at 5000 rpm. Right, time to get one of those fancy Electrex jobs. Got an Electrex RR, too for good measure. I installed them with the new battery.... 11.8 volts with the lights on at idle! Went back through the entire harness, replaced the fuse block with a new ATC style, contact spray / dielectric on everything, checked with GS Resources troubleshoot chart as well as the one from the Electrosport site - it boils down to the stator AC output at 5000 rpm being 46.5v, consistent on all three!!! Has anyone heard of problems with the rotor / magnets becoming worn, or am I just having some bad luck here??!! BTW, no "spare parts" when I pulled the cover...everything LOOKS correct. The outputs will get to 52v AC if I rev it to about 8k rpm. I'm sure Electrosport will warranty the stator, I'm just alarmed at the consistency between the old and the new. Anybody?

[posplayr]

I'm no materials scientist

but the rotor magnets have to be intact and provide adequate magnetic flux (i.e. be strong enough).

Heat or shock could ruin the magnets. I guess they can get old???

Bottom line, weak rotor magnets could explain the consistency.

That is why, I warned here recently about a Rotor/Clutch assembly on e-bay that looked to have been heated too much. Not saying yours was; it could be cumulative stress from engine vibration for all I know.

Posplayr

[J Paster]

Well, I do live in Phoenix...

Thanks for your opinion. When I went through the bottom end of the engine last year after I initially purchased it, I tried in vain to get that sucker off the crank in order to change the oil seal. No amount of slide hammering would get that thing off, so I gave up and elected to work around it then sealed the cases back up using the same oil seal. It was fine for about a year exactly, then failed during the hottest part of the year here in Phoenix. The bike does need valve guides and uses a bit of oil, but I never let it get out of the sight glass - I don't believe I would've overheated the magnets from letting them run too low on oil; however, I purchased it with 41k miles so I can't speak for it's previous treatment.

[posplayr]

Overheating

I meant using a propane torch or a Mapp gas torch to get the rotor off. You can do that ; I have done it, just be careful to keep the heat on the hub and off of the magnets. It apparently takes about 400 degF to melt the Red Loctite that should have been used on the rotor nut. If you did alot of banging, it could be that you stressed the magnets.

Using the heat avoids much of the banging. The lesser of two evils.

I used to do testing in military airdrop (stuff from planes). We usually had a magnetic compass installed and had issues with magnetized pallets. I dont think I ever did it, but the conventional wisdom was to use big hammers to bang on the steel pallet. The shock would reduce the parasitic magnetic Field built up in the metal.

Posplayr

[J Paster]

Heating it up

Thanks for the tip regarding getting the rotor off. I believe, if I remember right, the bolt came out of the crank OK, but are you saying I should heat the hub to help ease removal of it, or were you referring to the loctite on the bolt that goes in the end of the crank? I'm hoping the heat eases removal, because I definitely didn't try that. My plans are to verify with Electrosport that there's nothing else they have to say about this (Can't call until Monday), and take another good look at that rotor. I saw the rotor / clutch you were talking about on ebay; I'll get one locally - our local salvage yard has alot of old GS bikes that have engines intact. They usually let me remove my own stuff out in the yard.
Here's to hoping they don't want both arms and a leg.

[posplayr]

I'm no pro

But have been through 1 GS750 hub that fell off like nothing. And two GS1100 hubs.

The first 1100 hub was a bi&*Atch. Yea the nuts come off easy enough but you are supposed to put lockitie on the tappered part of the crankshaft and that is what gets really stuck I think. Propane is not hot enough. Mapp gas is much hotter.

http://www.idealtruevalue.com/servlet/the-178436/Detail

I damaged my own puller the first time when only using propane and then retapped the puller to put in a larger hardened bolt with more threads inside the puller. It is now HD. Teh HD puller and Mapp gas worked fairly easily (need a breaker bar and a long wrench to hold the rotor) when I had to pull the rotor back off again recently.

BTW, it cost me about $50 for tap and die to fix my $40 puller

Jim

[J Paster]

Much Obliged

That's the part I didn't know. Thanks for the info, I'm sure that's why I never could get it to budge. Now I can finally install that new oil seal (If I can find it)! Got some mapp gas in the garage. If Electrosport doesn't feel that it's the stator, I'll let you know if it was indeed a mysterious magnet failure.
Thanks,

John Paster

[psyguy]

just checking...
the symptom of low output voltage may come from using an 18-pole stator on a 12-pole rotor

[J Paster]

Poles?

Uh, let me check that. I'm going to remove the cover and inspect today; still have the original. I did verify that the Part number on the box matched up with the invoice, Electrosport PN# ESG020, which is the correct one according to their catalog. I did, however, notice upon installation that the new stator was thicker overall than the original. I'll count the poles once I get the cover off.

[J Paster]

Mystery crud

OK, I have pulled the cover to inspect the pole count vs. the OEM that I removed. I count 18 poles for both. I DID notice some mystery crud buildup between three of the poles. Looks almost like carbon or something. The buildup actually touches the contacts from each pole together. This stator has 50 miles since brand new. Wonder if that could be giving me a problem?!
I'll pull the stator again and investigate further; maybe I can remove this stuff. BTW, magnets look good - no cracks or signs of heat. In my most unprofessional opinion, they all have consistent field vs. the other. Using the old stator sitting in place, the feel of resistance when I pull it out seems the same as past experience.

[posplayr]

Interesting

I DID notice some mystery crud buildup between three of the poles.

Got pics?

Pos

[J Paster]

Not so mystery crud

Well, once I pulled off the stator and looked at it, I realized that was extra stuff put there by Electrosport where they attach the three leads. Scared me there for a minute. I've got it in the box - I'm going to pose the magnet question to them tomorrow. If they haven't heard of that issue, we'll just try another stator.
Here's a shot of my skunk. Hopefully I get it back on the road soon. I'll keep you posted.

[SqDancerLynn1]

Have you verified the meter readings to be acurate ??

[J Paster]

Yep

I've used two different meters, one of which I know is accurate.

[psyguy]

pre 1980 gs definitely use the 12 pole systems so your rotor is most likely a 12-pole setup (unless it has been replaced)
so, 18 pole stator wont work as it should

do a search on the forums - it has been well documented
or ask a new question in the tech forum

keep us posted