Help... (sorry to be "that" guy) Fouled plugs. Ignition? Other? Worse?

[TurboPerfecto]

Friends, sorry to be needy here. I am stumped: My 1982 fires up fine. Runs for about 3 minutes and plugs are FOULED black. Plugs are correct rating for my jetting, etc. (bike has been running fine for years with no problems until now). My carbs are tuned and synced, air and fuel are all flowing. No leaks around carb boots or otherwise. So I turn to my ignition: Coil seems fine (currently double checking). Spark plugs and wires seem fine. The PO has swapped out the points ignition for electronic ignition (has been running fine for a long while). Is it possible that my ignition (CDI?) has failed? Or simply possible that a wire has come loose / failed somewhere in the ignition circuit and I need to check that? Or...?? thank you!

 

[member28833]

Hello Portland, over in Vancouver.
With just a few more clues as to the ignition perhaps members could nail this down for you.
I am curious as to whether you can clip a timing light on it and watch the light condition and timing setting? (both sides) as it is running briefly. Maybe then you would learn more of the ignition systems performance and which direction to go next.
-RT

 

[TurboPerfecto]

I am curious as to whether you can clip a timing light on it and watch the light condition and timing setting? (both sides) as it is running briefly. Maybe then you would learn more of the ignition systems performance and which direction to go next.

Thank you very much for this. You're not the first one to suggest it. I BELIEVE the timing is fine but will double check. I'm going into a shop (Legion Moto Co. here nearby my house!) this Wednesday with all the tools / toys to check this. (Are you in Vancouver, WA?) Cheers

 

[member28833]

Yes, Vancouver WA,
Hey, once in the past I had a very good diagnosing experience at "Cycle Metrics" up in the Portland west hills. Gary is very familiar with Yamahas of our XS era.
Nice private one man shop.
-R

 

[jetmechmarty]

Yes, Vancouver WA,
Hey, once in the past I had a very good diagnosing experience at "Cycle Metrics" up in the Portland west hills. Gary is very familiar with Yamahas of our XS era.
Nice private one man shop.
-R

I just had a very good diagnosing experience right here at XS650.com. They diagnosed my XS1100 sooty plugs and terrible fuel mileage. Thanks to 5twins, gggGary, Jim, and I'm very sorry if I left someone out. My gas guzzling XS1100 was correctly diagnosed and repaired. It was worn emulsion tubes (needle jets) and jet needles. Economy jumped over 10 mpg after replacing those components.

 

[TurboPerfecto]

thank you @Machine and @jetmechmarty - I'm headed out with my multimeter to check ignition system now. Planning to look at the timing on Wednesday. I'll let ya know what I find!

 

[member28833]

TurboPerfecto, if you find your spark to be reliable and head back to the carbs, consider this.
You stated it was a points ignition model which says you most likely still have the BS38 carbs. Those old brass floats could by now be leaking resulting in float level and an over rich condition .
If it were mine, I'd confirm float condition as well.
-R

 

[gggGary]

My 1982 fires up fine.

An 82 came from the factory with an electronic (TCI) ignition, pickups on the stator frame (LH round cover) and a "black box" under the battery box. That's what your picture shows.
Always have spark plugs connected and grounded when cranking engine. Do that, crank the motor and look for bright blue spark on both sides. Report back and maybe take a couple pics of the bike that we can see. BOTH plugs are black like that? The 82 also used a handlebar mounted choke lever, check to be sure the slide bar at the front of the carbs is moving freely and returning fully to the "choke off" position.
Put a catch pan under the float bowls drain out the gas, is there any crud in the float bowls? You can run some more gas through the carbs and into your catch bowl by using the "prime" position on the petcock. An oil bottle cut like this works well to catch gas from the float bowls. Might be better without the jog on the sides.

 

[member28833]

Nice gggGary "82"
Scratch the brass float concern eh..

 

[TurboPerfecto]

TurboPerfecto, if you find your spark to be reliable and head back to the carbs, consider this.
You stated it was a points ignition model which says you most likely still have the BS38 carbs. Those old brass floats could by now be leaking resulting in float level and an over rich condition .
If it were mine, I'd confirm float condition as well.
-R

I appreciate this insight - I believe I have the 34 carbs - plastic floats. Float level, jets, needles, diaphragms all seem to check out and are clean + in good shape. I'm circling back to Ignition. It appears my secondary coil stage may have gone bad. I'm getting second and third opinions with the multimeter today. Could a failed coil cause the plug fouling as per the above pic? I wonder

 

[5twins]

Well obviously, it hasn't failed completely or it wouldn't spark at all. If the plug caps are originals, they may be going bad. Measure the resistance through them to see if it's risen above spec.

 

[TurboPerfecto]

An 82 came from the factory with an electronic (TCI) ignition, pickups on the stator frame (LH round cover) and a "black box" under the battery box. That's what your picture shows.
Always have spark plugs connected and grounded when cranking engine. Do that, crank the motor and look for bright blue spark on both sides. Report back and maybe take a couple pics of the bike that we can see. BOTH plugs are black like that? The 82 also used a handlebar mounted choke lever, check to be sure the slide bar at the front of the carbs is moving freely and returning fully to the "choke off" position.
Put a catch pan under the float bowls drain out the gas, is there any crud in the float bowls? You can run some more gas through the carbs and into your catch bowl by using the "prime" position on the petcock. An oil bottle cut like this works well to catch gas from the float bowls. Might be better without the jog on the sides.
View attachment 156147

@5twins @gggGary @Machine happy Friday. I just did some troubleshooting and here's what I'm staring at (and to answer your questions!):
- spark plugs / wires are all new. Spark plugs are proper heat rating.
- tested coil - coil is good
- choke is fine / no crud in float bowls
Here's some info that is starting to add up, and me deducing what the suspect may be:
- my battery doesn't seem to be charging when the bike runs
- since both my plugs are fouled black (assuming carbs / fuel / air mix is basically good)
- is it possible that ignition system is failing somewhere? (can failed ignition cause black dry fouled plugs? It only runs for about 3 minutes before they're totally fouled)
- and it is possible that the sensor (what is it called?) on my copper.. what's it called - that spins around - has failed? (is this the suspect?)
**my theory... if the sensor has failed, then the ignition wouldn't be firing correctly (fouled plugs) and battery not charging ..
... does this sound like it adds up? I realize this could be impossible on a message board. Ha. But thank you for your insight! (pics attached)

and a pic of the carbs etc if you care

no jokes about my petcock being off plz I have it ON when the bike is running

 

[TurboPerfecto]

Hello Portland, over in Vancouver.
With just a few more clues as to the ignition perhaps members could nail this down for you.
I am curious as to whether you can clip a timing light on it and watch the light condition and timing setting? (both sides) as it is running briefly. Maybe then you would learn more of the ignition systems performance and which direction to go next.
-RT

I will see if I can do this! thank you

 

[Bushyeyed1]

To be honest I would try and not over think it. Start with checking out the carburetors. There has to be a reason it’s running rich at idle. Maybe something as simple as an o-ring on the air fuel mix screw. One more thing did you just install those pod filters?

 

[TurboPerfecto]

To be honest I would try and not over think it. Start with checking out the carburetors. There has to be a reason it’s running rich at idle. Maybe something as simple as an o-ring on the air fuel mix screw. One more thing did you just install those pod filters?

Good questions - Guy at shop here in Portland threw on those pod filters because he had them lying around. I believe we properly tuned my mix screws and synced carbs to those. (we started at 1.5 turn out which is stock and then ... I can't remember, will double check today) Prior to that it had foam pod filters which were starting to deteriorate. The o-rings are good (recently replaced and checked.), carb jets / diaphragms, etc all check out. I will see if I can take a closer look at the mix screw question. I'm getting into territory where I dial in the mix screw so lean that the bike doesn't keep running at idle. But I will tinker with it some more today... Thank you!

 

[5twins]

You have the BS34 carbs which came set up very lean and E.P.A. strangled from the factory. While mix screw setting specs may be in the 1 to 2.25 turns out range for the earlier, richer jetted BS38s, these 34s usually need about 3 turns out on a stock or near stock machine. If you've done intake and exhaust mods, and re-jetted the carbs for that (especially a larger pilot jet), then the mix screw setting needed may be less, maybe in the 2 to 2.5 turns out range. But I doubt you'd ever need less than 2 turns out.

 

[member28833]

Googled your shop. "Legion Moto Co." in Portland.. Great reviews for being growing local motorcyclist hangout! Shop/Lift space for riders, Mechanics near by. Even though in your XS's case it seems your "tuning" is not quite right yet, I look forward to visiting your shop idea.
If you do truly need local assistance, (besides me lol) ps: I have a good rotor/stator for your XS.. remember Gary @ Cycle Metrics. He is Goood

 

[5twins]

If you're not charging, that could be the root of all your problems. The bike will run for a while off the power in the battery but as that power gets low, the ignition will begin to act up.

 

[Jim]

Those pleated filters have been known to cause problems with the CV carbs. Have you tried running the bike without them?

 

[gggGary]

As an experiment remove the pod filters, see if that changes how it runs. If no change, reinstall.
Then; fully charge your battery in the shop, unplug the voltage regulator, (6 wire connector, by the frame backbone above the filters) see how it runs. With a good battery you should get an easy 15, 20 minutes of running before the battery starts to weaken. The headlight will not come on. IF it runs better with the voltage regulator disconnected that's a sign you may have a weak "sensor" magnet on the rotor. There are some easy work arounds for that.
Yes get a voltmeter on it, look for about 12 volts idling and 13 up to 14 volts once the motor is revving above 1500 up to 3000 and above RPM. Voltage should NOT get to 15.
If charging is weak clean, all connections including grounds.
check fuse box, especially ignition fuse, wiggle fuses see if it changes how it's running.