Expanded charging system guide (In progress)

[gggGary]

It's the custom builders with um mixed heritage bikes, with brew your own wiring systems that fight the hardest. Wiring diagrams are SO unforgiving of the slightest differences. Not to mention trying to run a bike with no or a bad battery will eat up and spit out charging systems about as fast as you can throw new parts at them. I have repaired at least 10 or 12 XS650 charging systems. The tests aren't that hard to do if you are methodical but a LOT of guys are positive electrical is hard and tricky and then prove it on their bike. Cluelessly messing around with a non functioning charging system will often add a second problem before fixing the first, then it's hard to sort them out. Odds are good any old non runner XS650 you buy will have some charging system issue. If you fix it BEFORE tearing everything apart and building your own harness, life will be much simpler.

 

[peanut]

absolutely Gary

its amazing how some are so willing to tear down and replace everything rather than apply some simple test proceedures first.

Guides such as yours are a real blessing to those that know how to use them .All the relevant information in one place with pictures

 

[Kerry]

Are failed rotors a common problem on the XS650? After numerous tests, it's starting to look like that is in fact my problem. Cheers, Kerry.

 

[gggGary]

Yes
#1 is trying to use a DEAD battery
#2 is worn brushes
#3 bad fuse box on the 4 fuse models
#4 is a failed (shorted) rotor
then in more or less random order
failed stator windings
bad voltage regulator, rectifier
bad or broken wires, dirty connectors, switch contacts.
Typical "barn bike" issues.

 

[Scrambled]

Barn bike issues could be mice chewed wires .

 

[XSLeo]

Ohm testing the rotor will determine if it's bad. The reasons gggGary listed are prominate one.
I agree with #1. weak or bad batteries have low voltage even at thier best. This low voltage keeps the rotor "turned on" most of the time trying to keep the bad battery charged. This constant "on" creates excessive heat in the rotor windings. The heat cooks the insulation on the wire in the winding. When the insulation burns away, the wires short to each other, reducing the amount of wire actually used. Less wire reduces the magnetic feild created. The low ohm reading is the indication of shorted wires.
Leo

 

[peanut]

I've noticed that some rotor's seem to get rusty too ?

The crank surface behind the rotor ,that the crank oil seal sits on has got really rusty and deeply pitted on my bike ,probably from many years of sitting around unused in the UK climate. Theres plenty of rust on the rotor too as there is lots of steel in the rotor.
(79xs650SF US bike imported to UK in 1997)

 

[XSLeo]

The rust won't hurt the way the rotor works much. They all get a bit rusty. They live in a place that gets hot as the bike runs, then cools off while it sits. The heating up expands the air around the rotor. This expanded air goes out the bleed hole on the bottom of the cover. As things cool down it draws in fresh air. If this fresh air holds moisture it can condense on the cool prats inside the alternator. The stator and rotor.
bare steel and moisture and oxygen together cause rust.
Some some should be expected, but it won't hurt the function of the rotor and stator as long as it's not so much the rotor gets stuck inside the stator.
Leo

 

[peanut]

I guess rain is not going to be as much of a problem in most of the US like it is in the UK.
Our cars and bikes rust like you wouldn't believe.

I would suspect that its not just condensation that has caused 1mm+ of deep rust pitting on the crankshaft of my bike , its years of being being left out in all weathers and never getting dried off in a nice warm garage.

The curious thing for me though is the fact that the worst of the rust occurred underneath the main crankshaft oil seal bearing face where you would expect it to be lubricated with engine oil and protected from the effects of oxidation.

 

[XSLeo]

As an engine runs gas blow by from the rings, moisture and other contaminates collect in the oil. These things turn to acid. If you engine sat very long these acids might be what rusted your crank.
A good polish on those rusty areas should fix it right up.
Leo

 

[stanleyh]

Mr xs Leo , I have a 78 - 79 model. I just rewired a lot of the bike last night. No voltage drop feeding the rect reg all in one. I have a couple ? s. With the rct reg I see seperate orange and blue. I have the blue hooked to the switched hot "brown wire and I have all the voltage. I have the orange wire to the regrect hooked to the neg. I understand the 3 yellows on the 6 pin hook to the 3 whites coming out of stator. Only remaining wires in 6 pin conn out of reg rect are green and red. ? I have no voltage on the brushes. Shouldn't I get some kind of voltage on the red or the green going to the brushes. ? I don't right now. Do the brushes ground or not. I have seen so many diagrams my heads spinning. lol Desperate a/c electrician getting rear kicked by this one part. I have new rotor, and stator "mikesxs", battery, brushes, wiring, fuse block. Any help would make my day, thanks stan

 

[gggGary]

 

[peanut]

Mr xs Leo , I have a 78 - 79 model. I just rewired a lot of the bike last night. No voltage drop feeding the rect reg all in one. I have a couple ? s. With the rct reg I see seperate orange and blue. I have the blue hooked to the switched hot "brown wire and I have all the voltage. I have the orange wire to the regrect hooked to the neg. I understand the 3 yellows on the 6 pin hook to the 3 whites coming out of stator. Only remaining wires in 6 pin conn out of reg rect are green and red. ? I have no voltage on the brushes. Shouldn't I get some kind of voltage on the red or the green going to the brushes. ? I don't right now. Do the brushes ground or not. I have seen so many diagrams my heads spinning. lol Desperate a/c electrician getting rear kicked by this one part. I have new rotor, and stator "mikesxs", battery, brushes, wiring, fuse block. Any help would make my day, thanks stan

have a look at the tech section ...this tech guide should helphttp://www.xs650.com/forum/showthread.php?t=6477

 

[krevin]

Alright, I know it's an old thread but I used it for my charging problems. First off I went through the tests in order when you get to the third step is where I am stuck. I did everything I can but I cannot get the voltage going to the brushes to be any more than 1 volt less than the battery. I checked the 3prong plug behind the headlight and the red is exactly what the battery is. Now when checking the brown it is 1 volt less. Again I tried to repair the brown circuit. I went through every brown wire. Here's the thing I disconnect the wire that leads to the brushes and the brown wire at the 3prong behind the head light is exactly what the battery is. I am thinking the stator is bad but I am asking on here because of the $200 price tag to confirm. I understand electrical pretty well but I am hoping I am wrong and just missed something. Also, to further check I disconnected the brown wire from the plug with the green, red or brown depending what you believe, and the 3 white wires. After doing so I connected a new wire and ran it straight down to the brushes to see if it would fix it and again the voltage at the brush is down 1 volt roughly. I disconnected the wire from the brushes and tested the voltage that the "replacement" wire was carrying and it was exactly the battery at 12.88v. So I am hoping I overlooked something, please tell me what I missed or I think I am going to take this bike out to pasture.

 

[gggGary]

Hmm lets explora bit more what are you getting for a reading across the slip rings on the rotor? and what are you getting from stator white wire to white wire when it's unplugged?

I will guess your rotor is reading below 5 ohms ring to ring. Some voltage drop at the rotor is kind of expected, 12 volts into 5 ohms gives about a 2.4 amp draw, that is a pretty heavy draw. I think my point is that a 1 volt drop at the brushes will not stop the bike from charging, you need to keep testing. What happens with the slap test? Are you getting any charging at all? Have you removed and checked the brushes?
What year is the bike?

 

[Kerry]

Alright, I know it's an old thread but I used it for my charging problems. First off I went through the tests in order when you get to the third step is where I am stuck. I did everything I can but I cannot get the voltage going to the brushes to be any more than 1 volt less than the battery. I checked the 3prong plug behind the headlight and the red is exactly what the battery is. Now when checking the brown it is 1 volt less. Again I tried to repair the brown circuit. I went through every brown wire. Here's the thing I disconnect the wire that leads to the brushes and the brown wire at the 3prong behind the head light is exactly what the battery is. I am thinking the stator is bad but I am asking on here because of the $200 price tag to confirm. I understand electrical pretty well but I am hoping I am wrong and just missed something. Also, to further check I disconnected the brown wire from the plug with the green, red or brown depending what you believe, and the 3 white wires. After doing so I connected a new wire and ran it straight down to the brushes to see if it would fix it and again the voltage at the brush is down 1 volt roughly. I disconnected the wire from the brushes and tested the voltage that the "replacement" wire was carrying and it was exactly the battery at 12.88v. So I am hoping I overlooked something, please tell me what I missed or I think I am going to take this bike out to pasture.

Hi Krevin. Sorry but I won't be much help here as such things are over my head as far as electrical goes. I ended up solving my charging problem by having a friend re-wind my rotor. Rather than forking out the $200 for a new one, we bought some copper wire for $25 and a high heat resistant epoxy to seal it in. This appears to have solved my charging problem, after ruling out the other possibilities like regulator, rectifier, brushes, etc. I know I did have a melted plug with the 3 wires, so there was a possibility of something very wrong here also... But replacing the rotor has definitely sorted things out for the time being. (Touch wood)! And the bike is currently behaving itself. Sorry I can't be more helpful but my mechanical & electrical knowledge is limited. I wish you good luck..and hope you can solve this problem. It's always a shame to see an old bike 'put out to pasture'. Cheers, Kerry.

 

[krevin]

It is a 81 I replaced the brushes because the others wires had worn off. Slap test is spot on and ohm reading was wack on my one digital, reading 148, so I had to go a buy a different one and low and behold it reads 2.4. So I guess I should keep going down the list than. On a side note the slap test does draw the wrench just as in the picture but I have no idea how strong is strong or weak is weak.

 

[gggGary]

It is a 81
it reads 2.4.

2.4 across the slip rings is VERY low (toast), normal is about 5.4 did you mean 5.4?

That low reading would go along with your 1 volt drop at the brushes.
putting a draw of 5 amps on the battery.
An internally shorted rotor reading very low ohms is rather common.

 

[krevin]

Yes sir 2.4 is correct. This is something that is common? Also would this be something PO could have caused? He had a camera battery rated at 1.5amps that he bought at radio shack hidden in the headlight. The bike when I bought it had a wire harness that was chopped all to hell. I have replaced everything meaning I bought a used harness and installed. The rectifier was bad so I did the homemade one. The PO took off all lights and gauges to compensate for the small battery which I had to recreate brackets and bought an all in one gauge cluster which worked when the battery was charged lol. It looks pretty good but that doesn't mean nothing if it doesn't run/stay charged.

 

[gggGary]

If you read this thread (and at least 50 others) you will find yes an internally shorted rotor is common and yes we think a PO's shenanigans are often the cause of a toasted rotor. Hard to tell if your PO caused the rotor problem or he was willing to do anything but fix the "real" problem.

You may see and heed advice to replace the whole charging system with a PMA set up and that is very popular, BUT you would also need to replace your ignition with a Pamco set up if you do that (also very popular). To use your stock charging system you will need to get a 81-83 TCI type rotor from a reputable source, the TCI rotor has a small magnet that is the signal to fire the plugs. Earlier rotors do not have the magnet. Some rotor rebuilders do not keep the magnet at the correct depth and create ignition problems.