Can Someone Explain Ignition System on 1982 XS650 Special?

[Jim]

R/W is power in
Brown is ground side.... power out that goes to the box....
... tell ya what, jus' tell me where you got the 11v from, the R/W or the brown?

Fwiw, it's easy to test a coil (any coil) real world. Disconnect the brown wire and intermittently... and rapidly touch it to ground... you know tap tap tap...
Every time you tap it, the plugs should fire. Do they?

I'm assuming you read the caution about having BOTH plugs grounded when testing the TCI system?

 

[Jim]

That 11v was to the coil with the run switch on

So... you're lookin' at a volt.... volt and a half drop from the battery to the coil. You need to chase that down. Dirty iggy switch.... kill switch... or a corroded connection.
You'll want less than a half a volt drop at the coil for the system to reliably work.

 

[fenbrancis]

I’ve got 11 v from the r/w wire to the ground

 

[fenbrancis]

So... you're lookin' at a volt.... volt and a half drop from the battery to the coil. You need to chase that down. Dirty iggy switch.... kill switch... or a corroded connection.
You'll want less than a half a volt drop at the coil for the system to reliably work.

Will take a look into that next. Other than starting and working backwards (along with a diagram) any other things that may cause firing issue or you think low voltage to the coil is definitely a good starting point?

Also I read that plugs should always be grounded on these, (mine were) but why is that?

 

[Jim]

or you think low voltage to the coil is definitely a good starting point?

Not saying that's the problem, I'm saying we need to eliminate that as a cause by fixing it. Troubleshooting is a process of elimination.

Also I read that plugs should always be grounded on these, (mine were) but why is that?

The coil floats... no internal ground in the secondary. Both plugs need to be grounded to complete the circuit.

 

[fenbrancis]

Not saying that's the problem, I'm saying we need to eliminate that as a cause by fixing it. Troubleshooting is a process of elimination.


The coil floats... no internal ground in the secondary. Both plugs need to be grounded to complete the circuit.

Sounds good, I’ll do some investigative work on my switches, plugs, and any connections and see if I can find anything.

Will get back to you, thanks for all of the help and insight!

 

[Jim]

Look for loose or corroded connectors... and not just the iggy ones.... any connector or ground.
The key switch is a favorite place for voltage drop. It too can be cleaned. Have a read here. Might be some variations 'tween it and your switch, but it's a good guide to go by.

 

[Jan_P]

Lets keep this simple
Most problems I believe is imperfect circuit Top -- Down
Battery appears be OK but 11 V at the coils starts to get borderline Low.
Even if kick staring is tried -- with e --starter it can drop even further and some electronic Ignitions just
Shuts down ..
There is no mention of Wiring status or service on connectors
If it was me I would ensure ground connections and try to up the 11 V at ignition parts
And Consider to kick start for a while at least until machine is dialed in.

I would also ASAP ---that is first time bike starts check charging voltage across the battery it is easy to do and can give insights on other things like a shorted rotor.

Fuse holder and kill switch is next.

 

[fenbrancis]

Bike has been kicked for the most part only used the estart when the bike is warmed up.

Not trying to get to in depth as probably best to stay one issue at a time but, when I first got the bike the head light wouldn’t work. I pulled the stator and cleaned the brushes, and the rotor and light came on, continuity on the rotor was good. However, when the bike is revved to 5000 rpm it doesn’t spike super high on voltage

 

[fenbrancis]

Lets keep this simple
Most problems I believe is imperfect circuit Top -- Down
Battery appears be OK but 11 V at the coils starts to get borderline Low.
Even if kick staring is tried -- with e --starter it can drop even further and some electronic Ignitions just
Shuts down ..
There is no mention of Wiring status or service on connectors
If it was me I would ensure ground connections and try to up the 11 V at ignition parts
And Consider to kick start for a while at least until machine is dialed in.

I would also ASAP ---that is first time bike starts check charging voltage across the battery it is easy to do and can give insights on other things like a shorted rotor.

Fuse holder and kill switch is next.

Would it be smart to assume the imperfect circuit (to begin with) is likely in a switch or connection and probably hold on unraveling the whole wiring harness until each connection and switch has been checked

 

[Jan_P]

Would it be smart to assume the imperfect circuit (to begin with) is likely in a switch or connection and probably hold on unraveling the whole wiring harness until each connection and switch has been checked

Yes Sir -- if you ask me it is well over 90 % perhaps even over 95 % of the cases that the problem exits in a connector switch
or moving part lock fuse holder or so -- If the wire is bad it happens in wet weather and still is rare . At least in the climate here
We have far more problems with water than heat and sun.
Only time a wire shorts ( Generally speaking ) is if goes against something hot engine or exhaust and the insulation burns or gets pinched somewhere
As I understand you are after a standstill. It is normal to service the connectors .. I use some carborundum paper and a little contact grease ( I Use copper grease .perhaps you call it anti seize ) but there are other better Not to much so the grease shorts
If the goal is to start the bike go for the ignition circuit first ..and special attention to ground connections
Which is not a connector or moving part But very important .. Can even be the only thing you need to do
Check at the battery also. from minus

 

[fenbrancis]

Thank you for the help and insight! Give it a super in depth look, I appreciate it!

Keep you all updated

 

[sleddog83]

There is an excellent tci troubleshooting write up at https://www.650central.com/if_your_xs650_with_standard_yama.htm
Or do a search for If your xs650 with standard yamaha electronic Ignition has no spark

The only thing I would amend is at step 6 measure the pickup coil resistance by disconnecting the ignitor and measuring at the connector. No need to remove the pickup coils to test them.

Only thing I would note so far is your secondary coil resistance seems low. Check it again as per step 8 in the procedure. The coil resistance you measured might mean a weak coil. Note that you are checking it from plug cap to plug cap.

11 volts is marginal for running the bike. A weak battery and a weak coil could be causing some problems.

 

[fenbrancis]

Hi all, got the digital multi out today.

Battery was at 12.4v fresh
Voltage into the coil was 11.8v (drop seems normal)
Primary coil test between 2.7 and 3.1
Secondary coil test 11.87 (plug caps pulled, wires check)
Ignition switch clean
Voltage into start switch 11.8
Pick up circuit test on both wires rendered 760 ohms

All plugs and connections look clean

 

[fenbrancis]

There is an excellent tci troubleshooting write up at https://www.650central.com/if_your_xs650_with_standard_yama.htm
Or do a search for If your xs650 with standard yamaha electronic Ignition has no spark

The only thing I would amend is at step 6 measure the pickup coil resistance by disconnecting the ignitor and measuring at the connector. No need to remove the pickup coils to test them.

Only thing I would note so far is your secondary coil resistance seems low. Check it again as per step 8 in the procedure. The coil resistance you measured might mean a weak coil. Note that you are checking it from plug cap to plug cap.

11 volts is marginal for running the bike. A weak battery and a weak coil could be causing some problems.

Hey sled dog, been following by this this afternoon. I popped the tci box open the other day and everything looked okay (doesn’t mean it is) anyone know if there is a way to test that's

 

[sleddog83]

I built my own tester and use it along with an oscilloscope. About the only thing you can do is examine it closely for burnt components and check the input diodes using your meter. I always offer my services for repairing them, but the reality is that the cost of shipping the unit back and forth is prohibitive. The other thing to check visually on these boards is the solder. Cold solder joints over the whole board or overheated solder joints around the +12v r/w, gnd bla, output ora connections. You could try reflowing the solder on them just on spec.

 

[fenbrancis]

I built my own tester and use it along with an oscilloscope. About the only thing you can do is examine it closely for burnt components and check the input diodes using your meter. I always offer my services for repairing them, but the reality is that the cost of shipping the unit back and forth is prohibitive. The other thing to check visually on these boards is the solder. Cold solder joints over the whole board or overheated solder joints around the +12v r/w, gnd bla, output ora connections. You could try reflowing the solder on them just on spec.

Ah, yeah I opened it the other day. By mo means am I an expert on electrical engineering or electronics but I didn’t see any broken resistors, fried parts, or solders that were touching.

I wanted to ask, is there any way to test that starter circuit relay?

 

[sleddog83]

Do you mean the relay for engaging the Starter? Is the starter also not working? In terms of the ignitor, there is a set of relays....clutch and sidestand that will disable the tci board. I believe you just remove them. If you want to check it. Put a voltmeter on that pin on the ignitor connector. If there is a ground there then the ignitor output is disabled. I will dig my notes out tomorrow morning to confirm this one with the color code of the wire.

 

[Jan_P]

Off topic but can interest
I have recently been trying to repair old 70 ies HiFi equipment. Mixed success
There is apparently the possibility to measure components temperature with an IR thermometer.
One points the laser dot on the object and it reads the temperature
I bought a meter a $ 30 yesterday ( So I dont know much about it now )
If one can power the electronics up ( For a TCI on the bench ) one should be able to read the temperatures .If open circuit cold and if a capacitor
getting old at times it gets hot and can be detected

 

[fenbrancis]

Do you mean the relay for engaging the Starter? Is the starter also not working? In terms of the ignitor, there is a set of relays....clutch and sidestand that will disable the tci board. I believe you just remove them. If you want to check it. Put a voltmeter on that pin on the ignitor connector. If there is a ground there then the ignitor output is disabled. I will dig my notes out tomorrow morning to confirm this one with the color code of the wire.

Ah yeah that’s what I mean, no the starter cranks just fine.