See if you can figure this puzzle out!

[Guest]

Got an issue with the charging system on my bike (big surprise!), and I am a bit stumped.

Also, I confess that at first, I didn't know the first thing about motorcycle maintenance or repair if any kind. Fear not, cuz I have since cured myself if that ignorance.

So first a little background. Sorry if this takes long to read, but in this situation, the devil is in the details.

Bought an 81 GS400 L last August from Kijiji. As far as I knew, the bike had been reasonably well maintained, with no serious issues.

First day I had it, the battery died.

My brother-in-law, who is an electrician and pretty handy with the mechanics, took a look at it. I don't exactly know what he did with the bike, but it seemed to start run fine after he got it back to me.

A few weeks later, my headlight bulb went while riding in the daytime. So I switched to the high beam just so I could stay visible, and within minutes, that burned out too. Then the battery died again.

Told my brother in law, he said it was the rectifier/regulator. I cheap'd out and bought a salvage rectifier, however it wasn't a Suzuki rectifier. The guy I bought it from (who had been in the motorcycle salvage parts business for over 25 years, and really seemed to know what he was talking about) told me it was from a Yamaha, and that it should work better than the factory Suzuki rectifier, as was his experience.

I installed the salvage rectifier, but I never had a chance to bring it to my brother-in-law to test it with a volt meter before winter hit. I also checked the battery and discovered that it didn't have a single drop of water left in it. I refilled it and charged it, but it still seemed kind of moody, sometimes it kept a charge, sometimes it wouldn't.

So this spring I decided to shuck out the money and buy a brand new battery. The bike seemed to do well with the salvage rectifier and the new battery, but I didn't drive it with the headlight on in case the rectifier wasn't performing properly and I didn't want to blow out the bulb again.

I was finally able to get the rectifier checked with a volt meter, and if I remember correctly, it was showing 12 volts at 4000 rpm (I think it is supposed to perform at 14). After that, I decided I could drive the bike with the headlight on, fairly sure that I wouldn't have any more problems.

Wrong.

I had driven the bike a few times after that, using the high beam during the daytime to help stay visible on the road. The next time I tried to start the bike, the battery was too low to crank it over. So I charged the battery, and tried driving with just the headlight on low beam. There's seemed to be no problem, the battery held it's charge and the bike continued to start without a problem.

I decided to go for a brand new rectifier, and ordered one specifically for my bike from a company called RMStator. The new rectifier ($62 plus $12 shipping) arrived this week, and I promptly installed it in the bike, thinking that all my battery charging woes were finally over.

Once again, wrong.

I drove to work and back the next day. That evening, I took the bike to the gas station to fuel up, and the battery died. Again.

So now I'm not sure what to do. The new rectifier is brand new, and according to the website, made specifically for my model bike, but it obviously wasn't doing the job at charging the battery.

Basically, the breakdown is this:
New battery + salvage rectifier - high beam = bike starts no problem

New battery + new rectifier = battery too weak to start.

What to do??

Did I perhaps install the new rectifier wrong?

Is my stator shot?

Is my new battery FUBAR'd from draining it off too many times?

Is there perhaps a bad connection somewhere that is grounding out?

I put the salvage rectifier back into the bike, and once my battery has been recharged, I'll try to drive the bike around and see what happens.

I plan on testing the brand new rectifier with a volt meter whenever I get a chance to bring it to my brother-in-law's place, but in the meantime, I'll do what I can in my own.

Any suggestions? Ideas? Solutions?

[tom203]

Please do the quick test in this link and report all 6 results

http://www.thegsresources.com/_forum/showthread.php?p=1272192#post1272192

This will let others narrow your problem down.
It's too bad you didn't notice the R/R advice here before buying the RM unit

[fyarl666]

Thanks, that seems like a great place to start with. I think I will steal a volt meter from my dad this weekend so I don't need to rely on my brother-in-law to help when his schedule allows.

[tkent02]

A really cheap meter ( less than $10) is more than adequate for these tests, and anything else on an old bike, if you don't want to wait.

HF has one for about $8 that will work fine.

[fyarl666]

Tried the checks in that quick test link, and the voltage on the battery didn't increase at all once I started the bike, leading me to believe the stator is at fault. Gonna do a few more tests to make sure, but pretty confident the rectifier isn't the issue and the battery is still good.

[posplayr]

Tried the checks in that quick test link, and the voltage on the battery didn't increase at all once I started the bike, leading me to believe the stator is at fault. Gonna do a few more tests to make sure, but pretty confident the rectifier isn't the issue and the battery is still good.

taking your word on it, with new R/R that the stator is bad. Do revised Phase B tests and report those results.

[fyarl666]

Did the phase B test by trying to take an AC voltage reading off the stator wires while revving the engine to 4-5000 rpm. After trying several different variation texts, my official AC voltage reading from my stator is a big fat ZERO.

So now I get the triple play, new battery, new R/R, and a new stator. Should run like a dream come true once it's all done.

[tom203]

Make sure you understand your meter's positions. Put meter on AC voltage scale of 200 and check house outlet- you should see about 120 volts. Use this same meter position and check the phase B stuff on your bike running at 4000 rpm.

[mrbill5491]

So now I get the triple play, new battery, new R/R, and a new stator. Should run like a dream come true once it's all done.

You got it, only use a new type series RR when your ready to fix it. Oh yeah clean and replace any damaged electrical connections while your at it. Might want to add another ground to the mix as well.