I thought I was an ok mechanic untill.....

Do you think I should make a new wiring harness? If so does someone have a good wiring diagram that would help eliminate the extra crap?

 

You sig says you have a parts bike. What kind of shape is ITS harness and/or electrics in?

I still think your safety circuit has your TCI grounded.

 

Here is the relevant part of the schematic. As you can see, it's not that complicated. There are no safety circuits that ground the TCI and it will not crank if the kill switch is off.

I agree with SQLGuy. If the wiring is correct and the resistance and voltages are fine, it might be time for a scope.

By the way, does the rest of the electrical system work? The signal lights, brake lights, horn, indicator lights? Did you try another pickup? Heck, is the battery in backwards?

 

Everything works except the horn and the headlight. But I've been told the head light doesn't get power until the engine is spinning at a certain rpm. So the horn doesn't work. I have tail light, break light, turns. I'll look into switching the harness off my parts bike.

 

What does the scope do? Hows it work?

 

An Oscilloscope is a device that creates visual representations of electrical signals. You can learn more about them at http://en.wikipedia.org/wiki/Oscilloscope. They can be had fairly cheap these days and are useful for more than a few things.

 

Thats a bit over my head. Bigfitz, for the most part all the electrics are good with the exception that the wiring harness was painted over. Theres gotta be something more we can do.

 

Sure Tiny, shoot me a round trip ticket to your place and we'll figure it out in short order...Tiny? Tiny?
I'm sure it is something simple that we have just overlooked. Have you gone through the checklist as suggested by SQLGuy?

 

Bypass all the safety crap. Apparently earlier bikes such as yours don't disable the TCI so I'm stumped too except SOMETHING ain't right.

Basics: If it's not an open circuit then somethng is shorted to ground.

Swap coils off the parts bike.

OFF/RUN/OFF switch: bypassed or known to be good?
Wire rubbed through?
Wire broken inside its insulation?
Have you tried a set of BRAND NEW PLUGS, now? (shot in the dark, I admit.)

SHAZAM :idea: I just had an idea. Wait until dark. With the tank off, try to start the bike. See if you can SEE anything. You might get some lucky blue lightning somewhere and find it.

I'm just grasping at straws, you're there and we're here (wherever here or there is.)

 

One other thing that occurred to me... did you verify the ground from the TCI box back to the engine and (-) battery terminal?

 

I will try the going out when it's dark and seeing if I spot a short somewhere. Now for another question. I was taking the tci box off and it hit the frame and sparked. Should there be power running along the metal plate on the back of the box?

 

Hope everyone realizes that the '80-1 XJ650 TCI's only have 4 pins (or terminals) per connector, unlike all of the others which have 5 in one slot and 4 in the other. The larger slot on the '80-1 TCI will accept the larger 6-position connector like the later models.........but only has 4 terminals to plug into

Depending on what year HARNESS you are usuing, you may have a plug with a single wire that is doing "nothing" when plugged into a '80-1 box, and although I haven't traced the wire diagram, I'm thinking that the 5th terminal (not present on the '80-1 boxes) is where the TCI ground was moved to on the 5-terminal boxes, since the 5-terminal boxes were used on bikes WITH a sidestand safety switch, and my understanding is that the safety system on these bikes works by grounding the TCI, correct? So if the 5th terminal is the ground for the entire TCI, and it's no longer there/in a different position........

 

OOH OOH ME me pick me;

No, seriously, Len's right. If the harness/TCI don't match, the TCI will be ungrounded. SQLGuy may have just hit it, but from a different direction.

MY bright idea, which doesn't seem so bright anymore (I like "no ground at all" better) is: DIODE PACK Is it there; does your bike's ignition/TCI use one one of the diodes in the pack; and have you tested to be sure the necessary diode isn't bad?

I can only throw theories, the early 650 is quite a bit different from the 550s of the same years. Mine HAVE a separate sidestand relay and safety relay, and the safety circuit grounds out the TCI.

 

I just went out and made sure the tci and harness match. Anymore ideas or should I just put it on craigslist? I won't pay someone to fix it.

 

Where is this diode pack? I haven't seen one.

 

Normally inside the headlight housing "bucket".............a flat, rubbery things with 4, 5, or 6 wires going into it, about half the size of a pack of cigarettes. Different # of wires/different diode blocks for different models.........

 

I think I found it. Five wires running into it. Now how do I test it?

 

If the diode is the issue does chacal have them?

 

But of course.........

 

The Haynes manual has the checkout for the diode block on page 246. It says that the G model 650 has a diode block with two diodes and a resistor but provides no schematic for them. Testing is accomplished by replacement only it seems (unless someone has a good one they will willingly hack open to check for posterity). Does anyone have one handy to test out against the wire colors and post the table?

 

I'll try pulling the one off my parts bike and see if that helps. With my luck going the way it is the one of the parts bike will be garbage also. I'm so close to giving up and putting the thing on craigslist. You guys are the only thing keeping this project going at this point. I'm frustrated beyond words and I tried taking a week break a little while ago but it was still in the back of my head nagging me. So don't try telling me to walk away for a bit. The next time I have to walk away it's sold. What the hell is this diode for anyways? Its not on the wiring diagram I have.

 

Maybe check for continuity between the TCI connector and wherever those wires go elsewhere on the bike? Also verify the connections in the connector are good/not bent, etc.

I know this has been said before, but here it goes again:

These things are actually pretty simple. A coil fires when the engine is at a specific place regarding it's rotation. The TCI uses the pickups to decided when to fire the coil.

Thats it, isn't it? No other weirdness, no other systems involved, etc.

So: if the coils are getting power: Are they getting enough? Pull the battery from your car and hook it up via jumper cables? Maybe not a good idea. Check for poor connections (I am sure you are tired of doing this), check ohms - should be 0 or damn near.

Is there a way to manually 'fire' a coil? There has to be a tool somewhere that can cause a coil to shock the ever-loving-crap out of you or someone you love.

If the coils work, then does the TCI work? Check to verify GROUND, and 12v. Again, good power? nearly 0ohms, etc? What makes the TCI do it's thing? From the schematic posted above it looks like the only inputs are the pickups. Verify 0ohms between TCI and pickup coils. Verify no bent connectors, etc.

Could you use a chunk of steel or a magnet to 'fool' the TCI into firing a coil? Could firing a coil when the engine is not spinning hurt it? Plugs removed of course. Maybe someone could put a volt meter on the pickups to see what kind of voltage they are putting out and you could simulate it with a battery (I would expect 5volts via a 47k ohm resistor or so should do it..).

If the TCI seems to be good, then the pickups are next. Is the thing that spins bent, does it spin when you try to start the bike? (no idea why it wouldn't, but simple things first. On that note, you are getting compression, etc?) Check for 0ohms from the pickups to the TCI, things that are bent, etc.


With your meter on continuity (where it 'beeps' if you touch leads together) hold one lead on the neg battery terminal then touch the other to every pad on the TCI, with the harness disconnected, then on the harness pads. Should do this with the + term of the battery disconnected.

When it it beeps (and it should at some point) look at the schematic and make sure it should.

Then do this with the + terminal (neg battery term disconnected, but + connected).

How good is the ground between the battery, frame, and engine? I know some engines use a grounding strap, maybe even a grounding wire direct from the battery? 0 ohms...

Look at the schematic, you should have continuity and nearly 0ohms resistance between any connections connected by a straight line. Any squiggle marks have different values.

You said you verified the TCI is made for this harness. How?

I wish I could help, I love a good mystery.

 

I made sure the tci had only four connections at the large plug and the harness the same. I have cleaned the ground conections on the bike and plan on replacing the ground cables in the next couple days. Can anyone tell me what the point of the diode does?

 

Diodes only allow electrical current to flow one way (in one direction; they act like a one-way valve). For many electrical components this necessary for circuit protection and proper operation. Many voltmeters or multi-meters have a "diode-checking" function which is basically a first-one-way, then-the-other-way continuity test....a functioning diode will allow electricity to flow in one direction but not in the other.

So you can actually check the diode blocks, there should be schematcis in the service and that dreaded, horrible electrical section of the Haynes manual, which also gives you the resistor values for the resistor that is also part of the "diode block" on one of the circuit pathes.

 

I have the yamaha service manual and have read through the electrical section three times and haven't seen a damn thing on the diode. How much is a new one?

 

The diodes show up in the wiring diagram simply as a triangle stabbing a box; the method of testing is to use a meter and test in one "direction" then switch your leads and test. They should ony have continuity one way, and be open the other. My factory 550 book doesn't say diddly about them either. I can't tell you which actual circuits they're used in on your bike.

 

Thanks. I think I found it on my diagram.

 

Nope. Didn't find it on the diagram. Does anyone know what this damn thing is for? ie lights or starter or what? And why the hell can't I find it on my diagram?

 

If this diagram that was posted earlier in this thread is in fact the correct one for the bike, then there's no interlocks or diodes in the ignition circuit at all... They are red herrings.



You've got a 20A fuse, the key switch, a 10A fuse, and the engine stop switch... That's all! I can't imagine someone making changes to the bike to put some safety stuff ON it, right?

If the fuses are good and the switches are closed, you should have +12 on the R/W wire and (with the TCI connectors plugged in) a good ground connection on all the black wires.

After that, if the TCI, pickups, and coils are all good, you should get a spark. :?: :?:

 

So then could I check for voltage changes while the engine turns over to see if the pickups are good? My gut says it has something to do with the pickups.

 

I don't know if you can successfully test the pickups with a meter.

Burnarr; You're right, but here's something to keep in mind: Those "isolated circuit" diagrams are NOT the same as the wiring diagram. Not every circuit has its own "discreet" wiring; they share power feeds and grounds, etc. The solution will be found in the master wiring diagram I believe.

I think it's a WIRING problem that may not be actually part of the ignition CIRCUIT but is instead part of a different circuit that is sharing some of the same wiring. The diode pack was a guess that fit that parameter; I'm grasping at straws too.

 

I'm thinking I might splice into all the grounds for the bike and run a wire straight to the battery. If that solves my problem then I'll make a new harness

 

Yeah, good point. That's why it would be important to verify the voltages under question right at the TCI and that's also exactly why I included the little detail of "(with the TCI connectors plugged in)" when I was talking about checking the grounds above.

My only experience is with my 550, but on that bike, the ground side connection of the pickup coils is actually made inside the TCI and looking at the diagram for the 650, I bet they do the exact same thing. This means that if you unplug the TCI connectors, that "ground" to the pickups won't be a ground anymore. It'll be a floating no-connect despite the fact that it's a black wire and looks like it should be a ground, and it really IS a ground, but only if the TCI is connected properly. :lol:

With the TCI plugged in, all the black wires should be good connections to ground, so if you've got +12 on the R/W wire (RIGHT THERE AT THE TCI) and a good ground connections on all the black wires (RIGHT THERE AT THE TCI), a working TCI, working pickups, and working coils, you should get sparks.

And that simplicity is what makes this problem so interesting!

Sure can. For a static check you can obviously use an ohmmeter to check the resistance of the pickup coils. Unplug the TCI connector and check the resistance of the pickup coil winding.

If that looks OK, then plug the connectors back in and while cranking, you can see the pickup coil signal change as the crank spins. The only complication is that it's a small D/C signal with an even smaller A/C signal superimposed on it. At cranking speeds, it would be best to use an analog needle type meter for the testing instead of a digital meter. The signal will make a lot more sense on an analog meter.

You might be able to use a digital meter on a low A/C voltage setting, but the frequency is pretty low and I don't know how your typical digital meter will react to an A/C frequency that low. Probably depends on how smart the meter is... The smarter the meter, the less chance I give it of doing it right. :lol:

I just put an old Simpson analog meter on my 550 and got about 0.1VDC while sitting still and when I cranked it, I could see the needle rock back and forth around that 0.1VDC bias point as the crank spun. I assume your signals should be similar.

Burnarr

 

Hey Tiny,

I hate to ask again but did you make all those resistance and voltage checks from the TCI connectors? Were they in spec?

I've got an '81 XJ650 which is almost identical to yours. I can get some pickup readings for you while the engine is cranking if you like. I'm not sure how useful a voltage reading would be but it might help. I can also take some scope shots for comparison if you can get one to use.

 

With a meter on A/C, you'll probably be able to get a voltage signal from the pickups while cranking. That would be between ground and the orange wire (for one pickup) or the gray wire (for the other pickup). I'd expect just a few volts A/C during cranking, but 50V or more when running.

The right/better way to verify the signal they're producing, though, is with an oscilloscope.

 

It sounds like my volt meter being older than me is a good thing since its analog. Gitbox, I'm checking every wire on the harness from front to back even if its not part of the ignition system. When I am done or if something is off I'll let you know. Also I pulled the diode pack out of the headlight and it has a couple burn spots in it. I'll pull the one off of the parts bike and see if that helps anything.

 

The voltage on the pickups fluctuates when the relucter passes over them but it's minimal. How much needle bounce should I see?

 

Sounds like the pickup is working fine... Did you check both pickups, or just one?

I just put an old Simpson analog meter on my 550 and got about 0.1VDC while sitting still and when I cranked it, I could see the needle rock back and forth (a little) around that 0.1VDC bias point as the crank spun. Would depend on the sensitivity and reaction speed of your meter, but with my heavy loading, slow, old school Simpson analog, I saw it maybe rock back and forth from 0.0 to 0.2 VDC. I'm sure the peak voltage was actually higher and lower than that, but that's as fast as my meter would react.

My bike runs fine so I believe that signal level is normal and I assume your signals should be similar.

Burnarr

 

Burnarr, it' an AC signal, not DC.

 

I understand that, but when you've got an analog meter in your hands and don't have access to or experience with an oscilloscope, you try to make do with what you have, right?

You are correct, it's not a straight-up simple DC signal. But it's not a straight-up simple AC signal either...

The TCI biases the pickup signal to a DC level that is set by components that cannot possibly maintain a "perfect zero" voltage under all conditions and I'm not sure they even try. Not only that, but the pickups are not capacitively coupled to the TCI. They don't even bother to try to block that DC bias and I'm not sure they want to.

So that being said...

On my bike it's a 0.1 VDC signal with an A/C signal superimposed on it and while I haven't broken out the scope and actually determined the p-p voltage of that AC signal, I can tell you that my old analog meter can pick it up and makes it look like it swings 0.1 V in each direction around that 0.1 VDC bias.

Does that help?

 

I would take a look at the coils next...

You did measure the resistances of both sides of the coils, right?

 

I love it when the electrical guys go at each other like this.........

Now tell me this: do electrons really exist?

 

If by "electrons" you mean beer, and by "exist", you mean "chilling in my fridge", then yes, they certainly do.


Happy Friday!!

 

Exactly! You put on your magic decoder ring this morning, I see.......

 

Yes. I'm positive I lost one. :lol: :lol:

 

These lost electrons make me feel quite negative about this whole TCI issue.......

 

Even better Chac, do electrons "flow" or do the holes "flow"? lol

 

Haha! And that right there explains why that last geek humor missed you...

Two atoms walked into a bar.
First atom says to the other atom "I think I just lost an electron."
Second atom asks "Are you sure?"
First atom responds "Yeah, I'm positive."

Get it??? "I'm positive"

HAHAHAHAHAHAHAHAH!!!!! :lol:

Sorry.

 

Oh, and I'm not going at anyone... Sure hope I don't come off like that! Certainly not my intention and I apolgize if I did.

Burnarr

 

Hmmm........you or I may be ON to something..........like maybe an ION.........whew.

No, ya'll are great, I just find it humorous when potentials of definitional disagreements and polarity differences arise, which are always conductive to some high tension, alternating currents of electrical knowledge, philosophies, and information being bandied about in such a detailed manner, requiring a certain amount of inductive reasoning and logic for us lay people to try and grasp and get a Spark of insight from......