gt550 rectifier problem

[trouterspace]

My gt550 no longer charges the battery. I suspected that it was the rectifier or regulator so i bought a new electro-sport all-in-one rectifier/regulator. when changing it out, i noticed that the plastic connecter coming from the old rectifier was melted at the red wire. The new rectifier worked for a couple of days, but then stopped working. I assume i have a short or bad ground somewhere, however i know very very little about electricity and i basically don't know where to look for the problem. Can anyone point me in the right direction? this model 550 has 3 yellow wires and a red wire, but no black wire like i have seen in some diagrams and the clymer manual.

[Suzsmokeyallan]

If the connector melted on the old rectifier it means the connection was compromised and it overheated due to either a slack fitting connector, dirt or high resistance at that joint.
When you place a multimeter between the red wire in the connector on the electrical panel and any ground point on the frame you should see 12 volts, so check that first.
You may need to replace that same connector on the harness side of the electrical panel on the bike if its looking dark or also has heat issues on that socket.
The ground is the panel the components are bolted to which is in turn grounded to the frame by a short black wire strap. If your new part has a black wire you can also make a connection to the frame by using one of the battery box bolts which is where the ground strap for the electrical panel should also be as well.

[jabcb]

Could be just a wiring problem & the new rectifier/regular might be ok.

+1 on suzsmokeyallen's suggestions. Start with a visual inspection.

Does the rectifier/regulator look like its damaged?
Does the electric starter work?
Has it blown the fuse recently?

Do you have a multimeter?

Wiring diagrams for your bike are here: viewtopic.php?f=29&t=4743

[trouterspace]

When looking at the new regulator rectifier it looks fine, but it is a solid state, i don't really know what to look for for damage. The ground coming from the part was looking a little chalky, like perhaps it had gotten hot, so i cleaned that off.

When checking the red wire against the ground for voltage, do I want to set the multimeter on acv or dcv? ac before the rectifier, dc after?

the electrical starter works fine when the battery is charged up.

It has not blown any fuzes lately

I've noticed that the wire on one side of the main fuze gets warm, but not at the other side of the fuze. Does this have any implication?

[jabcb]

Good that the bike doesn't blow fuses & the starter works good.

One of the wires connecting to the fuse is likely frayed or damaged, which is causing that area to get warm.
Its not the cause of the charging problem, but it will need repairing. A good solution is a modern fuse+holder available at your local auto parts store.

As a starting point, you'll need to check the alternator stator or rotor.

Am busy for the next few days. I'll post more when I have the time.

[jabcb]

Alternator specs are on page 15 of: http://www.ozebook.com/compendium/suzi/suzidata1.htm

For stator, check resistance for each combination of two yellow wires at connector for rectifier.
Resistance should be nearly zero ohms.
Check resistance between any of these yellow wires & ground -- should be infinite.

For rotor, check resistance between ground and green wire at connector for voltage regulator.
Should be 2 to 5 ohms for Kokusan alternators & 10 to 20 ohms for Nippon Denso alternators.

You can tell which type of alternator you have by comparing it to the parts diagrams:
http://www.suzukipartshouse.com/home.as ... 6021160021
http://www.suzukipartshouse.com/home.as ... 6021160022

Its a good idea to check the brushes to see that they are intact, not worn out & the wire lead is still attached.


Variations in the wiring diagram are because Suzuki used two different rectifier wiring layouts.
Early rectifiers were grounded via the wiring harness (the additional black wire). Would have to check but I think this was actually a redundant ground because the rectifier was also grounded to the frame.
Later rectifiers used only the ground to the frame.

[pearljam724]

Another thing to consider. Find a better place to mount your new one, so that it is cooled more effeciently due to more air. The most common reason for rectifiers failing is over heating. Due to lack of air, long idle times in extreme temps or being mounted too closely to a high heat source or all three. Under a cover on the side of the bike, falls into that category. Expose the new one to more air when the bike is moving.

[trouterspace]

That is a good point, it does seem kind of silly to tuck it away under the side cover. Luckily it has been pretty cold lately here in upstate ny. I seem to have addressed the problem, although i didn't necessarily identify it. I cleaned a bunch of grounds and fixed a wonky wire, not sure which one was the culprit, but my battery seems to be staying charged. Lights are getting a lot brighter too. Thanks for all the help everyone!

I've got a different gt550j that won't spark at all, nothing from the starter, half the lights work, etc. I'll be sure to bug ya'll about that another day.

[jabcb]

Great. Problem fixed & you still have a little riding season left.

As a final check to make sure its ok, check the battery voltage to see what rpm it takes to start charging the battery & check the battery voltage after a good ride.

Modern rectifiers & rectifier/regulators are more efficient than the vintage parts from back in the 70s.
You get a smidgen more output & less heat. So heat will be less of a problem with modern parts.

[pearljam724]

Great. Problem fixed & you still have a little riding season left.

As a final check to make sure its ok, check the battery voltage to see what rpm it takes to start charging the battery & check the battery voltage after a good ride.

Modern rectifiers & rectifier/regulators are more efficient than the vintage parts from back in the 70s.
You get a smidgen more output & less heat. So heat will be less of a problem with modern parts.

The new parts may be better in regards to output and less heat. But, they still fail mainly due to over heating. I don't think that fact has ever improved. In fact, I think it's gotten worse. Go to different sport bike forums and read how often they fail. Suzuki for one had a recall back in 2010 on the GSXR's. Part of that recall, was mounting the new one somewhere else. Most OEM rectifiers are poorly made electronically. It's best to buy aftermarket and move it in a better location. Manufacturers on most models are more concerned with aesthetics. What a person may think of it sticking out in the open to allow more air. They often hide them and over heating is due to those reasons.

[jabcb]

+1 on heat problems getting worse.
Heat would be more of an issue with rectifier/regulators on modern bikes.

The T-series bikes use permanent magnet alternators with just adequate output.
They regulate alternator output by using a lighting coil that is switched on when the lights are on.
The T250/T350 don't have a voltage regulator. The T500 regulator doesn't have cooling fins.

The GT triples have higher output alternators, but the output is controlled by regulating power to the field coil.
So there is no excess alternator output.

A lot of modern bikes use high-output alternators with permanent magnet rotors.
The excess alternator output is converted to heat by the rectifier/regulator.
So the rectifier/regulator on modern bikes have a lot more heat to deal with the our GT tripples.
Manufacturers also enclose the engine with a fairing that also heats up the electrical parts.

[trouterspace]

Great. Problem fixed & you still have a little riding season left.

As a final check to make sure its ok, check the battery voltage to see what rpm it takes to start charging the battery & check the battery voltage after a good ride.

What rpm should the battery start charging at?

For me, winter=walking season. Last winter my riding season never ended thanks to mild weather. I'm currently in college and can't afford a car, all i've got is my Suzuki.

The battery is still charging, but I blew a fuze yesterday, plus blew out my headlamp bulb and taillight bulb. Hoping this won't happen again. What do you guys think?

[pearljam724]

Great. Problem fixed & you still have a little riding season left.

As a final check to make sure its ok, check the battery voltage to see what rpm it takes to start charging the battery & check the battery voltage after a good ride.

What rpm should the battery start charging at?

For me, winter=walking season. Last winter my riding season never ended thanks to mild weather. I'm currently in college and can't afford a car, all i've got is my Suzuki.

The battery is still charging, but I blew a fuze yesterday, plus blew out my headlamp bulb and taillight bulb. Hoping this won't happen again. What do you guys think?

Many people have the misconception of what a rectifier does. Many people think that the rec works like an alternator on a car. They think that the rec charges the battery like a car alternator does. It does not. On a car, you can have a dead battery and if driven the alternator will eventually charge the battery. If the battery is chargeable. On a bike it is different. The rectifier's main purpose is to not allow the battery to dip down below acceptable output levels. A rec will not charge a bike's battery. You most likely have a dead cell in your battery. If you have already replaced the rec. I would do two things if the problems persists after you charge the battery. Buy a new battery. If it continues, take the battery back for a refund. That will eliminate that factor. Check the stator for black burn marks and do a voltage test on it. You can buy a battery tester at Walmart for several dollars. Be sure to also charge the battery at 2 amps. A slow charge ( usually 10 to 12 hours ) is more affective than charging the battery quickly at 10 amps.

[jabcb]

Which Electro-Sport rectifier/regulator do you have? How did you wire it up?

[ConnerVT]

Many people have the misconception of what a rectifier does. ....

.... The rectifier's main purpose is to not allow the battery to dip down below acceptable output levels..... .

No.

The output for the from the Suzuki's generator is AC (Alternating Current), which is pulses of alternating positive and negative voltage. I would assume it looks like a dirty sine wave, from (depending on RPM) +/- 16 VAC

The rectifier converts this voltage to pulses of DC (Direct Current), which are pulses from 0 VDC to +16 VDC. The stock Suzuki rectifier is a full wave bridge rectifier, which the output inverts the negative voltage pulses to positive voltage.

The voltage regulator smooths out the DC voltage, and also shunts (bypasses to ground) any additional voltage over the regulator's set point (typically 13.6 VDC). On some old, smaller bikes, they do not use a voltage regulator, and instead use the battery to perform this function.

A voltage regulator can only output the voltage that is on its input. It can not make up power that isn't there. Typically the input voltage of a regulator needs to be 1.0 to 2.0 VDC greater than its output, due to voltage drops within the regulator itself.

Charging.jpg