ok im new to this forum. 2 days ago i bought a running 1990 suzuki gs500 for $250.00
it has some issues i need help with such as the motor doesnt recharge battery and cannot run on its own power, i found this out when i put a new battery in the bike and rode it a few blocks and the bike died. i tried to start it back up and the battery was dead. so i got it home charged the battery, started the bike and disconnected the bat and the bike died. so im assuming the bikes equivalent to an alternaotr isnt working. where do i locate and how could i fix the problem..

also i think i have a problem with the jetting/fuel mixture  on the carbs as when the bike gets warmed up it will bog down past 4k rpms where as when its cold it runs great... where are the mixture screws? and what are the specs on the adjustment for the bike?

and for the very last issue.... the tank had this yellowish film on the left side of tank below some bubbled up spots (rust) i began to wipe the film away and the takn began leaking! there is a small pinhole on the tank where i ruptured one of the small bubbled spots. there are 3-4 more spots like it.. now is there any way i can fix the tank or will i have to replace the tank and if so how much will that cost for a used tank?


thanks

Hi and welcome to the forums! 

It sounds like you got a pretty good deal for a fixer-upper! It's a good sign that the bike is running as-is. Now you just need to get to the fixing part:

Quote from: suzukimx4789 on February 19, 2008, 11:51:24 AM
the motor doesnt recharge battery and cannot run on its own power, i found this out when i put a new battery in the bike and rode it a few blocks and the bike died. i tried to start it back up and the battery was dead. so i got it home charged the battery, started the bike and disconnected the bat and the bike died. so im assuming the bikes equivalent to an alternaotr isnt working. where do i locate and how could i fix the problem..

So you are saying you installed a brand new battery (properly charged initially) and the bike died after a few blocks of riding?
I've never tried to do this, but I don't think the bike would happily run with the battery removed altogether.

Quote
also i think i have a problem with the jetting/fuel mixture  on the carbs as when the bike gets warmed up it will bog down past 4k rpms where as when its cold it runs great... where are the mixture screws? and what are the specs on the adjustment for the bike?

Have you first checked that the choke is not sticking. Does everything seem to move freely when you open/close the choke (the choke lever is on the left handlebar grip). The choke needs to be fully closed when the bike is warm.

Quote
and for the very last issue.... the tank had this yellowish film on the left side of tank below some bubbled up spots (rust) i began to wipe the film away and the takn began leaking! there is a small pinhole on the tank where i ruptured one of the small bubbled spots. there are 3-4 more spots like it.. now is there any way i can fix the tank or will i have to replace the tank and if so how much will that cost for a used tank?

Rust... yech! You can likely repair the tank by coating the inside (search for "Kreem" or "POR-15"). Otherwise, a used tank shouldn't be too hard to find.

Good luck with the bike!

Quote from: suzukimx4789 on February 19, 2008, 11:51:24 AMim assuming the bikes equivalent to an alternaotr isnt working. where do i locate and how could i fix the problem..

If you have a decent meter you should be able to pinpoint the problem (if any) in the charging system.  See [this FAQ thread].

Holler if you have any questions! 

Quote from: Kerry on February 19, 2008, 01:11:03 PM

Quote from: suzukimx4789 on February 19, 2008, 11:51:24 AMim assuming the bikes equivalent to an alternaotr isnt working. where do i locate and how could i fix the problem..

If you have a decent meter you should be able to pinpoint the problem (if any) in the charging system.  See [this FAQ thread].

Holler if you have any questions! 

thanks ill get out my meter and check it asap

let me be mr. positive-sunshine for a few minutes:

at least you found the charging and rust problems before you took off for an adventure

there, now i'm going back to moaning about carbs, people that stiff you for parts, and the weather. 

ok Kerry i tested the alternator as your instructions stated and here are the results....

ok my meter at RESISTANCE X 1 Just conecting the red and black probe together reads 21 ohms


this is my meter


white-blue + white-green result was 21 ohms



white-blue + yellow result was 21 ohms

white-green + yellow result was also 21 ohms

white-blue + ground result was 0 ohms

white-green + ground result was 0 ohms

yellow + ground result was 0 ohms too

what does this mean? i may have a short somewhere?

i went to do a voltage test be fore and while running off the battery and my DCV set at 25 didnt read anything on the battery?!
idk i kno very little bout meters when it comes to understanding them...but from what i can tell all mine will do is test ohms nothing else....i think its broken or fried so i will retest with digital meter tomorrow and post new results of the alternator ohm resistance, battery voltage before and while running, and regulator.
i can not test the ACV coming off the alternator at this time as the bike doesn't want to run at 5k rpm 

HERES A VID OF HOW THE BIKE RUNS WHEN ITS WARM
http://www.youtube.com/watch?v=wQmo00tHlWY

You meter looks like a plenty-capable model.  All it lacks is a DIODE function for testing the regulator/rectifier.  But before we draw conclusions using your readings, let's talk about a few things:

• When you put the meter in resistance-measuring mode, and touch the two probes together, you should get a reading of 0 ohms.  If the reading is higher than that (to the LEFT of 0 on the green scale), turn the OHMS ADJUST wheel until it does read 0 ohms.  (See the Measuring Resistance section on page 3 of the whopping [3-page Owner's Manual]. )  You'll probably find that each resistance range needs a different amount of adjustment.  If you can't get the needle all the way over to 0, the AA battery in your meter needs to be replaced.
   
  
• If you get 21 ohms when you touch the probes together, but 0 ohms when you measure a circuit, something is definitely wrong.  You may be measuring an "energized" circuit that somehow connects to both terminals of the motorcycle battery.  Are you sure you measured the wires that descend down to the alternator (hidden inside the left-side engine cover), and not the ones that connect into the main wiring harness?  The 3rd and 4th photos in the FAQ topic are misleading, because it looks like I'm measuring wires that come from above.  In reality, I'm measuring wires that "go below" but I did what I had to do to get the photos. 
  
  
• If the meter doesn't show a reading in the DC Volts ranges when you connect it to the MC battery, you may be hooking it up backwards. With the black probe plugged into the COM jack, and the red probe plugged into the VOA jack, touch the black probe to the negative battery terminal, and the red probe to the positive terminal.  You're probably doing this already, but just in case....

well i found out when i took the meter apart my dad had bypassed the fuse in my meter cus he blew it...i looked at some resistora on the meter and 2 of them are burnt/blackened so the meter is fried on the dcv and acv circuit cus my dad tried both for 110v outlets so idk if the ohms even work properly and as for the ohms adjustment.... it is set to the max lowest....i turn the knob the other way while touching the 2 probes together and the ohms reading goes up to 100+ ohms

ill borrow my neighbors meter tomorrow... he has a digital one that is much more accurate and i kno for sure it works

Quote from: suzukimx4789 on February 20, 2008, 01:37:37 AM
well i found out when i took the meter apart my dad had bypassed the fuse in my meter cus he blew it...i looked at some resistora on the meter and 2 of them are burnt/blackened so the meter is fried on the dcv and acv circuit cus my dad tried both for 110v outlets so idk if the ohms even work properly and as for the ohms adjustment.... it is set to the max lowest....i turn the knob the other way while touching the 2 probes together and the ohms reading goes up to 100+ ohms

ill borrow my neighbors meter tomorrow... he has a digital one that is much more accurate and i kno for sure it works

sears, $29               it's the only thing i've bought from sears in 10 years .

Coils are shorted to ground, but not to themselves ... how the F^(K ... think about it and then test it right. Take that F^(ker apart.
Cool.
Srinath.

Quote from: suzukimx4789 on February 20, 2008, 01:37:37 AMwell i found out when i took the meter apart my dad had bypassed the fuse in my meter cus he blew it...i looked at some resistora on the meter and 2 of them are burnt/blackened so the meter is fried on the dcv and acv circuit

Oops - dat not good.

Quote from: suzukimx4789 on February 20, 2008, 01:37:37 AMill borrow my neighbors meter tomorrow... he has a digital one that is much more accurate and i kno for sure it works

Good idea.  I went to Sears on Saturday, just to look around.  I ended up buying a [Mini Pocket Multimeter] for $20.  Not only is it small enough for my tool bag (and comes with a zippered, soft-side case) but it's auto-ranging!


One thing I could have done without, though.  The clerk at the register said, "I just bought one of these yesterday, on sale for $10.  You need to watch those sales!"

ok i retested with a digital  testing between the 3 wires comes out to 2.o ohms my neighbor said the alt is fine but when he tested the regulator he told me it was fried....so ill look for one at the salvage yard

anyways i pulled the carbs today and turned the mixture screws all the way in.... left carb was 2 1/2 turns out  and right carb was 5 1/4 turns out.  i reset them both to 2 3/4 turns out. its still running a bit rich so ill turn them in 1/4 turn each.

heres the result a much better running motor and slightly better throttle response
but the vacuum uh throttle things (not sure what they are called but they open by vacuum) well the left one bobs up and down when idle while the right side one does not. what is the cause of this and is it normal?

heres another vid as i'm horrible at describing things
   http://www.youtube.com/v/PP5ag87ls9I       

ok this is a little odd since i tested everything by kerry's instructions and reconnected everything im geting some charging it seems

when the bike is idle and the headlight is on high beam its like pulsating/fluxuating and when i give it some gas the pulsing stops at around 2500-3000 rpm and the light gets brighter untill about 6000 rpms then it dims to lower than when idle and pulses more.... something seems to either  be pulling some major voltage here or the regulator is totaly whacco........ why at 2-3k rpm does the alt and or regulator kick in and possibly kick off at 6k rpm..

Quote from: suzukimx4789 on February 20, 2008, 01:05:48 PMmy neighbor said the alt is fine but when he tested the regulator he told me it was fried

Hmmm ... I'd be curious to know more about his testing procedure and results....

Quote from: suzukimx4789 on February 20, 2008, 01:05:48 PMthe vacuum uh throttle things (not sure what they are called but they open by vacuum) well the left one bobs up and down when idle while the right side one does not. what is the cause of this and is it normal?

The right slide looks like it's moving a little bit, at least.  I'm guessing that you "just" need to balance the carbs.

----------------------------------------------

Quote from: suzukimx4789 on February 28, 2008, 07:22:19 PMwhy at 2-3k rpm does the alt and or regulator kick in and possibly kick off at 6k rpm..

Very strange.  If you get matching results when measuring DC Volts at the battery terminals at those RPMs, I'm at a loss.  If the battery terminal readings are fine, I would start (re?)checking connections somewhere between the battery and the lights.

Quote from: Kerry on March 01, 2008, 12:15:25 AM

The right slide looks like it's moving a little bit, at least.  I'm guessing that you "just" need to balance the carbs.

how do i do that? dont i need a special vacuum  reader thing?

bump....

I've got the same charging issue.  The bike will charge to 13V at about 2krpm but then will drop off to not charge at anything higher.  Mine runs good though. 
One time it did bog down when giving it gas untill I wiggled wires by the right side fiberglass under seat.  I think it was the thing that looks like a coil?

The Hayne's manual will explain how to balance carbs.

You will need a vacuum reader to measure the difference in vacuum between the right and left carb (the goal of balancing is to make this difference zero).

Fortunately, you can make you own balancer for just a few dollars: http://gstwins.com/gsboard/index.php?topic=3521.0