Bike won't start up and stay running

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

If you charge the battery on this bike, which is new (battery), it will run for a while, then die. The person I bought the bike from said that the charging system was bad, however, so far I am unable to do much testing since I cannot keep it running. Any suggestions on what is the problem with this bike? Thanks!

pamcopete

bobiii84,

If you have another battery, I would connect the ignition system to an external battery so it has nothing to do with the charging system. That will allow you to trouble shoot the charging system without the engine quiting.

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

Do you mean just hook up another battery in the dead ones place? Some of the tests say I need to have it running, for example to figure out if it's charging correctly. I think I have ruled out the rectifier cause we used an ohm meter on it and the diodes seem alright. Can you explain this to me as simply as possible? Sorry I'm new at this and want to make sure I'm doing this right. Thanks!

pamcopete

bobiii84,

Well, it would help if I knew what year / model bike you have as the ignition system is different from model to model. Assuming that you have a points system:

Leave the kill switch off for this test.

1. The second battery would just be sitting on the floor next to the bike.

2. Run a wire from the positive terminal(s) of the coils to the positive terminal of the battery that is sitting on the floor.
3. Run another wire from the frame of the bike to the negative terminal of the battery that is sitting on the floor.
4. Kick start the engine.

The ignition system will now be running on the battery that is sitting on the floor next to the bike so whatever is wrong with the charging system will not affect the engine.

Be sure to disconnect the wire going to the coils from the battery sitting on the floor to stop the engine and when the engine is not running.

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

First of all it's an 82 Yamaha XS650 Heritage Special. We went ahead and put a battery next to it and started it up (not from the coils, right from where the old one used to connect) and it started up but was not charging correctly. Instead of charging at 14.5 it was showing about 12.46 which may have just been what the battery was at. Then I checked the red wire coming from where the rectifier connects and grounded the other end, I read it at 12.1 and then I went down to where the charging system is and read 12.06 at the coils (I'm unfamiliar with all that area so sorry if I don't make sense) This is what we did so far today. Let me know if you have any advice and thanks.

xjwmx

There is a green wire that goes into the regulator. It's in the diagram you used to test the diodes in the rectifier. If you ground it and the voltage goes up, you're in luck, just build Pamcopetes cheap reg/rect combo. First check the brushes though if you havent. Next comes the troubleshooting procedure in the manual you can find online. Also, a bad battery can make a good charging system look bad, of course. If the battery will charge up on a charger it's at least passable.

P.S., on second thought, I'm not sure about the green wire test. Look it up in the manual....

dpmphoto

there's a charging system trouble shooting guide in the vault i believe.

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

Alright so noob question here. There are two parts that I'm not sure what the difference is between. There are two black rods with springs beneath them that roll along the rotor, what is this called? Also there is another piece that looks magnetic that has 2 metal circles on it's face, what is this? Sorry to be a pain, but I just don't know this, thanks!

gordo

I think your talking about the brushes for the rotor. And the other'thing' is the pickup for the TCI ignition.

nj1639

Would be good to get yourself a manual. Haynes is what I've got, hard to decypher some times.
y '83 sk H.S. had a problem with the charging rotor, relaceing that along with going through the entire wiring harness and cleaning up the connections fixed the problem.
Seems that the rotors can start to fail at around 9,000 miles, or maybe it's the years?
Check the vault or search for rotor testing.

jayel

bobiii84 wrote:

There are two black rods with springs beneath them that roll along the rotor, what is this called? Also there is another piece that looks magnetic that has 2 metal circles on it's face, what is this?

two black rods..... brushes
there is another piece 2 metal circles on it's face...... that is the rotor the brushes run on those two metal circles (slip rings)

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

Okay so we were testing the slip rings today for ohms because a guide on this site had it as a next step. So far we have been unable to get any reading off of the slip rings. Any clue why this would be? We may have done something wrong, I'm not sure. Also we are looking for the 3 white wires to check the stator. Are they the ones in the connector behind the left-rear cover or the ones toward the front by the carbs with thicker casing? Thanks!

pamcopete

bobiii84,

You are going to have to start using some common terminology here so we can under stand your problem better.

When you say you are not getting "any readings" off of the slip rings, do you mean you are reading zero "0" ohms or are you reading infinity ohms?

Zero ohms are what you get when you touch the test leads together. Infinity is what you get when nothing is touching the test leads.

People will often say that they are reading zero ohms, when in fact, they are reading infinity ohms.

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

Sorry for the confusion, I'm trying to make it as easy for you guys to understand me but I'm new to this.

Alright, when I tested the Ohms on the slip rings I got a reading of 1 so is that infinity? Also, earlier today I held a sewing needle of a thread next to the rotor cover and turned the bike to the run position. According to a charging system troubleshooting guide on this site the needle should've been pulled to the cover and stuck there but nothing happened. Is this indicative of a problem with the rotor or maybe the stator?

Your continued patience is much appreciated. Thanks

xsleo

When you turn the key on, battery voltage is sent to the brushes on the brown wire. It then goes thru the rotor, out the other brush, to the regulator on the green wire. The regulator grounds the green wire.
If everthing is working properly the battery voltage creates a strong magnetic field around the rotor. This will pull the needle against the case.
If the needle isn't pulled, then the rotor isn't creating a magnetic feild. This can be bad brushes, a bad connection in the wiring, bad rotor, bad regulator.
I would start by removing the brushes to check for length, 3/8" or longer. While the brushes are out is a good time to check the ohm's of the rotor. Probing thru the inner brush holder to get to the inner slip ring, the outer slip ring can be probed most any where. You should get about 5 ohms between the slip rings. Infinity from slip rings to ground.
If you follow the wiring harness that comes up by the drive chain to its first connector. This is where you can check the ohm's of the stator and the rectifier half of your combined regulator/ rectifier.
To check these parts unplug the connector. You will find three white wires in the connector. Three to the stator, three to the reg/rec.
The three white wires from the stator should have from 4.5 to 9 ohms between three sets of white wires. In your head number the white wires as 1, 2 and 3. Check the ohms on 1-2, 2-3, 1-3. They should read close to the same ohms. and infinity from the wires to ground.
I would suggest you get a repair manual, if you don't already have one. They are on ebay most of the time, or down load one at biker.net
The manual tells how to do these tests and a lot of others.
I would recommend checking all your fuses and fuse holders, The holders get pretty beat up in 26 plus years. A lot of folks replace the stock fuse holder with individual inline fuse holders. I like the blade type fuses, not the glass tube type fuses.
If the fuses and holders are bad they could be why it starts and quits.
If you can do these checks and let us know the results, we can help you get the bike charging. It's not as hard as it looks.

jayel

if it starts up but dies right away, (won't stay running) that's a carb/fuel problem

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

Thanks for all the help guys. Sorry I haven't posted any updates in awhile but the weather here has been pretty wet. (no garage Crying or Very sad

)

Anyways, I've come to the conclusion that the rotor is bad. When I tested from the slip rings to a ground and got infinity: the good news. When I tested in between the slip rings I didn't get the 5-5.5 ohms, just a 1: the bad news. So i guess it's off to looking for a rotor for me. I've been looking around for them but haven't found much. MikeXS has them but they're more than I'm willing to pay. Is there some alternative site that has them for cheap?

Also I've found this company, customrewind.com. He's got rewound rotors but then again they're $92. On the off chance, do any of you have a rotor that you wouldn't mind parting with?

As always, thanks for your time.

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

I've also been looking on eBay for them but it's very difficult to find my year specific rotor ('82). Does anyone know the parts interchange on these? Will an early 70's rotor solve my problems?

pamcopete

bobiii84,

If you are using the stock TCI ignition, then you must use a rotor from an '80 to '83 model because of the little magnet that is embedded in the rotor to trigger the sensors for the TCI.

Also, be sure you have the Ohmmeter set to the lowest scale when you measure the slip ring resistance. That is generally the 200 Ohm scale.

A rebuilt rotor is $125 from CustomRewind in Birmingham, AL, 800-798-7282. (talk to Gary) You might find one cheaper, but you won't find one better.

I would be leery of buying a used rotor on EBay.

You can also split the rotor and rewind it yourself with 300 ft. of 22 gauge enameled wire. There is a post here somewhere that describes how to do that.

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

Quote::

When I tested in between the slip rings I didn't get the 5-5.5 ohms, just a 1:

You tested for 5or so ohms with 1 tester lead on each slip ring, corect?

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

yes we tested between the slip rings (key on) and got a 1 instead of the 5 or 5.5 we should have gotten.

bobiii84 · Full Member Joined: Nov 17, 2009 Posts: 13

Well I've given it some thought, what do you guys think about the permanent magnet swap off of a rd/rz? It really doesn't look too hard to do and will cost me about the same as a rewound rotor.

If anyone has a permanent magnet system in their bike could they tell me if it has any big advantage over staying stock? What's it entail? As far as I understand it, I will need the rd/rz rotor and stator, a new regulator/rectifier, and a proper adapter plate. Right?

Will I be losing HP if I use this system because the unit will always be on pulling from the crankshaft?

This thread has really shifted directions and I appreciate the continued patience that you guys give me.

pamcopete

bobiii84 wrote:

yes we tested between the slip rings (key on) and got a 1 instead of the 5 or 5.5 we should have gotten.

When measuring for Ohms, you do not turn the key on. You should also have isolated the rings by removing the brushes so your reading will not be influenced by external circuitry, such as the regulator. Having the key on could also influence the reading, so try again.

gordo

bobii, if you go with the permanent magnet type alternator, you'll have to use the Pamco conversion, because there is no place to put the pickup for the ignition system.
There was a thread here some where about rewinding your rotor yourself. Not too bad of a job, just splitting the rotor is a hassel.

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