Rectifier/Charging Qurestions

[Rocketman]

I noticed lately that my battery on my 1982 GS850L seems to be taking longer and longer to get to a full charge on my Battery Tender (much longer than before) and the battery is only a year old.

Tested the alternator by unplugging and measuring between white/blue, white/green, and yellow wires. Based on 75 volts as the target, I came up with 89, 87 and 90 volts, so I guess the alternator is fine.

Testing regulator/rectifier...started at 13.24 volts with bike off and battery fully charged. Unplugged top two fuses in fuse box, and at 5,000 rpm, voltage across battery terminals read 13.45 volts. As per manual, over 15 or under 14 means a bad rectifier/regulator.

First, do you agree with this diagnosis?

Second, a new OEM regulator lists for $ 250! There are some aftermarket ones for between $99 and $140. Any specific recommendations for used Fleabay makes/models that will definitely work with my bike?

Part numbers on fiche show 32800-49X50 which replaces 32800-49310. Seems 650's, 750's, 850's and G's, Z's, etc have similar part numbers but not exact.
Some help would be greatly appreciated.
Thanks.

[mike_of_bbg]

Please do not buy an OEM r/r. Make sure you go through the whole stator papers tests and verify that your stator and wiring is all good first:

http://members.dslextreme.com/users/storagecliff/images/stator_check.pdf

http://www.thegsresources.com/garage/gs_statorfault.htm

There's some info here on r/r compatibility:

http://members.dslextreme.com/users/storagecliff1/images/stator_compat.html

Also see the sticky thread about compatible Shindengen units from Hondas (see mostly posts 1-3):

http://www.thegsresources.com/_forum/showthread.php?t=134690

These are preferred by many members over the stock Nippon Denso units.

[Nessism]

This is one of the most commonly discussed topics here at GSR. You are sort of reinventing the wheel with your questions here. Sorry to bash but that's the simple facts.

To answer your questions, it does seem like your R/R is toast but don't rule out wiring system problems.

There is a ton of info on this exact topic here... http://members.dslextreme.com/users/...dd-n-ends.html

I suggest you check your wiring first, and if necessary get a new/used R/R from ebay (off a Honda) and then adapt it to fit on your bike. Very easy.

Good luck

[TPL]

I'm in the same boat, same bike and same year. I found corroded and arcing connectors. I've decided the only responsible thing to do (since I plan on taking long trips) is to replace the stator and mosfet R/R and get it right, it is worth not being stranded far from home.

Read this thread: http://www.thegsresources.com/_forum...d.php?t=152769

[Rocketman]

Let me know which r/r you end up getting and how it worked please. Stator test will be in the works meantime.

[BassCliff]

Hi,

If you're riding every day, or most every day, you shouldn't have to leave your battery on a tender. I normally never have to put my battery on a tender. The only time I have put it on a tender was when I was waiting for a new stator to arrive. I would charge up the battery at night and commute to work the next day.

The first thing you should do is move the r/r ground wire and connect it directly to the negative terminal of the battery. Solder some extra length of wire if necessary. Check and clean all electrical connections and grounds. You will probably have to take off the seat, tank, and side covers to visually inspect and clean all of the connectors.

You'll find lots more information on my little website and by searching the forum. There are some updates to the Stator Papers that you should be aware of.

More On The Stator Papers

GS Charging System Health+Quick Test


Yes, this topic has been covered almost as much as tires and oil.


Thank you for your indulgence,

BassCliff

[TPL]

Let me know which r/r you end up getting and how it worked please. Stator test will be in the works meantime.

The R/R I'm getting is FH012AA SHINDENGEN MOSFET

My stator passes the ohm test and appears to be OK, but being 30 years old I just assume replace it. If your stator is bad you are welcome to mine for cheap.

Once I get all the parts rounded up I'll post a thread with pics.

[BassCliff]

Hi,

Let me know which r/r you end up getting and how it worked please. Stator test will be in the works meantime.

This is part of the collected information in the Electrical Odds and Ends section of my little website:

This is a list of more modern FET regulator/rectifier units compatible with Suzuki GS motorcycles.
See my Regulator/Rectifier Replacement guide.

*Honda CBR1000RR 08 Shindengen FH008EB 12V 40 Amp rating (with wire tails and plugs)
*Honda CBR1000RR 08 Shindengen FH014AA 12V 50 Amp rating
*Kawasaki ZX10/14, R1, FJR 05-06 Shindengen FH-010AA 12V 50A rating 14.3V -15.1V
*Kawasaki ZX10 2005 Shindengen FH-010BA 12V 50A rating 14.3V -15.1V (mounting holes 3 mm wider than GS, may need bracket)
*Yamaha FJR13 2007 Shindengen FH-012 12V 50 Amps rating 14.5V
*Yamaha FZS10 2007 Shindengen FH-012 12V 50 Amps rating 14.5V
*Yamaha RX1 03 Shindengen FH-001 12V 35 Amps rating 14.1V - 14.9
*Yamaha YZF-R1 02 Shindengen FH-001 12V 35 Amps rating 14.1V - 14.9V
*Yamaha YZF-R1 04-06 Shindengen FH-011AA 12V 50 Amps rating (has very tall fins, consider if enough space)
*Yamaha YZF-R1 2007 Shindengen FH-012 12V 50 Amps rating 14.5V
*Yamaha Snowmobile 07/08 Shindengen FH-012AA 12V 50 Amps rating 14.5V


There are lots on Ebay in the $20-$25 range. Please note that on any used r/r you will probably have to solder/crimp the proper connections for your bike.

Thank you for your indulgence,

BassCliff

[posplayr]

I noticed lately that my battery on my 1982 GS850L seems to be taking longer and longer to get to a full charge on my Battery Tender (much longer than before) and the battery is only a year old.

Tested the alternator by unplugging and measuring between white/blue, white/green, and yellow wires. Based on 75 volts as the target, I came up with 89, 87 and 90 volts, so I guess the alternator is fine.

Testing regulator/rectifier...started at 13.24 volts with bike off and battery fully charged. Unplugged top two fuses in fuse box, and at 5,000 rpm, voltage across battery terminals read 13.45 volts. As per manual, over 15 or under 14 means a bad rectifier/regulator.

First, do you agree with this diagnosis?

Second, a new OEM regulator lists for $ 250! There are some aftermarket ones for between $99 and $140. Any specific recommendations for used Fleabay makes/models that will definitely work with my bike?

Part numbers on fiche show 32800-49X50 which replaces 32800-49310. Seems 650's, 750's, 850's and G's, Z's, etc have similar part numbers but not exact.
Some help would be greatly appreciated.
Thanks.

Where in the manual is that test described? It is not described in the stator pages (either new or old)

Like TPL said you could have bad connectons but from your tests it is hard to tell
One other hint Suzuki was never very good at electrical stuff so I would not put too much faith in the manual on electrical test espeically your quoted criteria

[TPL]

Redoing the charging system to me is well worth the investment. It could be worse, I could be throwing 300 bucks at some stupid chrome piece for a Harley, yea, that makes a lotta sense...

[Rocketman]

Test was found in the Clymer's Manual for '79-'80 GS860 & GS1000's.

[Rocketman]

Thanks for the help and wealth of information, as always. Almost done with stator test, and so far, so good. Checked output of all 3 stator wires @ 4,000 rpm-all equal at 72.2v. Checked each stator leg for continuity to ground and got "OF" for all three legs. Reistance between each leg was between 0.5 and 0.7 ohms. Based on this, I think my stator is OK, but will pull the r/r ground, extend it to the negative battery terminal and see if it charges any higher than before. BTW, I don't use the bike everyday as I have another one, and I keep them both on the trickle charger 24/7 for many years with no issues. The Battery Tender Plus keeps the surface charge right where it needs to be.

[posplayr]

Test was found in the Clymer's Manual for '79-'80 GS860 & GS1000's.

So the clymer tests says to remove fuses in order to check a loaded charging system test (at 5K RPM)?

If you pulled the main fuse then you have decoupled the battery from the R/R; not much of a battey charging test.

http://www.thegsresources.com/_forum/showthread.php?t=152769

Finally STEP #3.) Perform Stator Paper Checks. The stator pages checks are not perfect, but they are designed to help you through a process of elimination in determining what is wrong with your charging system. The good news about doing steps #1 and #2 above first, is that when the stator pages say to check your connections you know you already have done it. Here is the update.


http://www.thegsresources.com/statorpapers4.php

Link to Revised PHASE A of Stator Pages:

[Rocketman]

Clymer's just says to pull the two fuses connected to the orange/red and orange/green wires. Can't really tell on mine, but I pulled the top two fuses, which is the headlight and one mystery one.

Anyway, I snipped off the connectors of all three stator wires and added shiny, clean connectors. I also extended the r/r ground and it is now connected directly the the battery negative terminal.

Here's the new readings:
Everything off...13.16v
At rest, ignition/headlight turned on...12.45v
Initial idle at 900-1000 rpm...12.70v
4,000 rpm.....13.90v
Secondary idle (after 4,000 rpm)...13.15v

I'm not seeing "around 14.5v" as recommended at 4,000 rpm, but it sure is close. And it seems to have improved by almost 1/2v by just relocating the ground and cleaning up a few connections. On second thought, I'm thinking things are OK (if not marginal) and it might not be time to replace the r/r. Anybody concur, or think I'm off base?

[posplayr]

Clymer's just says to pull the two fuses connected to the orange/red and orange/green wires. Can't really tell on mine, but I pulled the top two fuses, which is the headlight and one mystery one.

Anyway, I snipped off the connectors of all three stator wires and added shiny, clean connectors. I also extended the r/r ground and it is not connected directly the the battery negative terminal.

Here's the new readings:
Everything off...13.16v
At rest, ignition/headlight turned on...12.45v
Initial idle at 900-1000 rpm...12.70v
4,000 rpm.....13.90v
Secondary idle (after 4,000 rpm)...13.15v

I'm not seeing "around 14.5v" as recommended at 4,000 rpm, but it sure is close. And it seems to have improved by almost 1/2v by just relocating the ground and cleaning up a few connections. On second thought, I'm thinking things are OK (if not marginal) and it might not be time to replace the r/r. Anybody concur, or think I'm off base?

except for what ever cumulative damage your stator has, it appears perfectly functional. You still have some voltage drops, most likely in the fuse box and at the "T".

You should measure your voltage drops to confirm.
Revised PHASE A of Stator Pages

STEP #2 MEASURE POSITIVE LEAD VOLTAGE DROP

STEP #3 MEASURE NEGATIVE LEAD VOLTAGE DROP