Done some test, can't tell if it's battery or charging sys

[cmattina1]

78 Special.

I have read through the tech section regarding this issue, and found a thread where Leo was helping a guy with his issue... Anyways, My battery was tested good at Canadian Tire, and has a 13.2 charge after it sat on the charger till full. Measures 12.6 at idle. However, at 3000 rpm it only gets 13.6, so I got out the feeler guage to check the megnatism around the generator cover, turned the ignition on and BAM flew over to it, so I can only assume good magnatism... Could it be the battery? Or could it still be in the charging system?

 

[retiredgentleman]

cmattina1;

You're charging system is not delivering full voltage. You should be getting 14.2 to 14.5 volts at 3000 rpm.

First question............are the brushes at least 3/8" long? Did you measure the resistance from slip ring to slip ring (with brushes removed)? Should be around 5 ohms.

Here's a simple way to test if the regulator is giving the correct voltage to the rotor. Start and idle the engine. Put voltmeter + lead on the left brush, -lead on the right brush. At idle voltage should be +10 to +12 volts. Increase rpm to 2500 rpm and voltage should reduce to +6 or +7 volts. This shows that the regulator is working.

 

[cmattina1]

I went out and did these tests.

The brushes are longer than 3/8".
Voltage at idle: 11.6
Voltage at 2500 rpm: 12.6 So, it went up instead of down....

Resistence: meter would not give an accurate reading. On most settings it said 0. On 200, it gave me anywehre between 7 and 45

So, looks like i need a new rotor... could i need a stator also?

Also, I was wondering what your opinion is if I should be riding the bike at all right now, just in terms of battery health?

 

[retiredgentleman]

cmattina1;

The fact that you are getting 13.6 volts at 3000 rpm, means you are getting partial charging, but not full charging.

Measuring 12.6 volts at the brushes as you rev the engine, shows that the regulator is trying to increase alternator voltage, but its not happening.

Its a good sign for your rotor that you had a magnetic field when you did the feeler gauge test.

Its possible that you have a ground on the stator winding, which is pulling down the alternator output voltage.

Your meter is not working well on resistance................yes the 200 ohm scale is the right one to use for the slip rings. Cheap meter leads can also cause problems. You could try borrowing a better meter. It would be nice to know that the rotor ohms are in range. Since you are getting a magnetic field, lets just believe the rotor is working for now.

Lets move on to test the stator. Lets hope your meter measures AC voltage OK. If you follow the wiring from the alternator, you will come to a connector that is near the battery. There are 3 white wires in the connector ( maybe a dirty white). Leave the connector connected as per normal. Start and idle the engine. Select your meter to read AC volts on a low scale. Place your 2 meter probes into the back side of the connector and touch any 2 of the white leads. There are 3 combinations for the whites. Measure AC volts for all 3 combos. Tell us what the AC volts are.

 

[XSJoel]

The old charging system again. I haven't been here long, but I am amazed at how many times I have had to share this link:

http://xs650temp.proboards.com/index.cgi?board=Charging&action=display&thread=3461

I think we need a sticky.

 

[retiredgentleman]

XSJoel;

That link is in the "Tech" section at top of page. However, many riders are electrically challenged, and need assistance as they seek the holy grail..................a bike that charges properly

 

[XSJoel]

Yeah, I am electrically challenged and the fact that it could be a little more clearly written adds to the problem. Someone who knows their stuff should go back and clarify it.

 

[cmattina1]

I just got back from work so I will have to do the stator tests tomorrow. The problem with a lot of the tech section stuff, including that link joel offers is the terms are unfamilar to a new motorcycle owner. I know my multimeter reads voltage correctly, though, it could be off on ohms...

Also, I guess you are assuming that since I had magnatism the rotor is working, and since my ohm meter didn't show anything, it must be broken (because we already know there is magnatism)?

 

[cmattina1]

So, assuming that by there being only three combinations, it did not matter which was negative and which was positive.

C= Centre
R = Right
L = Left

CR = 12.6
LC = 12.6
LR = 13.6

Forget my last edit, if you read it. The above numbers are correct. I am not sure if they are good or bad...

However, I should mention that i went back out there to measure the charge at 3000rpm... I may have been measuring it wrong this whole time, meaning, I am a bit of an idiot... Regardless, I held it at 3000 rpm, while trying to keep the probes on the battery, kind hard to do while holding the meter also, anyways, after about 30seconds to a minute of holding everything steady the charge climbed to 14.8ish... I don't know if something was installed incorrectly and by tinkering a bit i reinstalled it, Or, there is lose connection in one of those white wires and when measuring them i "fixed" it.... I was just under the impression it should jump to 14.X, rather than climb at a bouth 0.1 volt a second...?

 

[retiredgentleman]

cmattina1;

Those AC voltage readings are in the correct range. The fact that one reading is higher, may indicate that the rectifier is faulty. Corroded connector pins (such as at the rectifier connector pins) can also cause high resistance.

Another area that causes problems is the old original (glass fuses) fuse panels. The fuse panel clips can increase their resistance. If your bike still has the old fuse panel, its best to replace with automotive blade type fuse holders.

With these bikes, the old original components such as the rectifier and regulator, while still working after all these years, are deteriorating and need to be replaced.

It appears that the rotor and stator are both working normally. The regulator also appears to be working.

I suggest you clean the pins on the rectifier connector, but the preferred thing to do is to replace the rectifier, which you can make up yourself.

http://xs650temp.proboards.com/index.cgi?board=Charging&action=display&thread=3473

If you still have the stock relay type regulator, I strongly recommend you replace it with a NOS automotive solid state type. I use the Standard VR-115 regulator.

 

[retiredgentleman]

OK, you edited while I was typing.

I'd say you have a healthy charging system. However, when you see 14.8 volts, it just means your regulator is gettting a little tired.

My comments still stand about the electrical components. Do yourself a favour and replace the fuse panel, rectifier and regulator.

 

[cmattina1]

Thanks,

I have the updated fuse set up, regulator is in the mail...

 

[XSLeo]

Quite often pulling apart the connectors and getting every thing bright and shiny and tightening the female halves will fix lots of the problems.
The slow voltage rise is the mechanical regulator, works much slower than a solid state regulator, even new they had problems with proper charging.
Doing the Crysler reg and Radio Shack rec is a great upgrade. With that installed your idle voltage my be 12.5 to 13 volts, as you rev it up most anything over about 1800-2000 rmps will give you a solid 14.5 volts and never go over at higher rpms.
Adding a volt gauge to the bike will help see trouble before it gets too bad and you have to push the bike home.
This one ain't to pretty but saved my butt the long push home.
Leo

 

[cmattina1]

Yeah I plan on buying a guage for sure. I have the regulator, but the rectifier costs about 60 in Canada now that radio shake doesn't carry the parts anymore. The local electronics shop wanted 20 for each dual bridge recitifier

 

[retiredgentleman]

$20 for each rectifier is just like stealing from that electronic shop!

I paid $5.99 each, just 2 years ago here in Calgary.

Have you tried looking around for other sources?

 

[cmattina1]

I'm in Thunder bay, pretty small city. We have one private shop and The Source. The source stopped carrying that part a few years ago, you must have just got it in time. However, a nice forum user has already offered to mail me some, so no worries.