Yes. Normally you'll start with a fully charged battery (in your case, you'd use a trickle charger to 'fill up' the battery overnight) - your bike will be running off of the battery for the duration of the test.

You'll disconnect the stator leads at the point closest to the stator before starting. Normally, you'll start the bike and rev it up to the test RPM point - normally between 3000 and 4500 RPM for most bikes (its useful to have help - someone to twist the throttle and someone to take the readings with your multimeter). Test each and every pairing combination - For a 'three wire' system: wires 1&2, 2&3, and 1&3 (or however many pairing combinations to account for the wires coming out of the stator). The voltage should be the same for each of the pairing combinations. Be aware that the plug coming out of the cover may have 'other wires' that are for other sensors/purposes. You'll only need to test the (normally thick) wires for the stator.

Hmm well the service manual only calls for a voltage reading across the battery terminals. At 5000 rpm it's only putting out 12.5V, which is less than the standing battery voltage of 13.5. So either the stator is fried, or the rectifier is fried. The manual just says to test the resistance across the stator wires, and that's OK so I'm assuming the rectifier is bad.

"Normally" the regulator/rectifier pack is the failure point in most motorcycle charging systems. It is simply reassuring to know if there is a voltage test for the stator/rotor output that would eliminate any doubt about the health of the coils in the stator. A resistance test is fine, but nothing would beat a voltage output check.

At this point, I'd go ahead and get a new R/R pack, and see what you get. :idk:

Yeah usually if the stator tests fine then its the rectifier

The GS series of Suzuki engines from the late 70's to mid 80's are pretty much bulletproof. But the charging system is problematic. A lot has to do with the grounds that don't because of corrosion. The best article I've seen on how to test a regulator, rectifier (my GS1000 came with separate regulator and rectifier), and stator is the famous "Stator Papers" on the GS Resources site: http://www.thegsresources.com/garage/gs_statorfacts.htm.

Rick's Motorsport Electrics, and Electrex make great electrical components. They can be had out of the Parts Unlimited book at your local shop.

i wired up 2 small computer fans over the R/R and when the bike is on the fans are on.

i've had 1 R/R go bad.

Good idea. There's never enough airflow over the R/R.

Also make sure you have a very good contacts at the 3 yellow wires plug. They tend to melt and over heat and take out the R/R if not.

Also make sure you mount the R/R to the stock location normally a piece of alumimum is there that transfers the heat away from th unit. I have seen lots of guys move them to a plastic mount or even leave them loose and then wonder why they keep going bad.

Do not charge a dead battery with your bike. Inother words if you ahve to jump start your bike take the battery off and use a charger not the bike to charge the battery. It over taxes the R/R.

Consider a larger heatsink Alumimum piece behind the R/R and or use a heat conductive liquid between them. (white stuff found between a transistor and heat sink) Can be bought at radio shack.

The fan is also a great idea. I had a F3 that would eat them and I installed a F4 R/R because it had a larger heatsink attached to it the F3 did not have any fins on the R/R.

Also make sure that new pipe is not putting more heat near the R/R. A lot of guys remove things like heat sheilds (sometimes a thick rubber mat) from there bikes cause they think its not for anything special. Its a heat sheild thats flexible. Be sure not to remove them.