No spark all 4

[le_bucheron]

I have stock coil but I think I burn it by unplug all 4 wires at the same time to check the compression. I read on the forum: Do not try to crank if your wires and spark plugs are not grounded... Now how can I check if my coils are good?

Or I just received my accel coils. I'm not sure if I should to find my problem with my old coils (if it's good) or use my accel...

Does I need to upgrade regulator/rect...? If yes what is the good and cheap way?

I have so many thing to learn on this 30 old project...

[CaptonZap]

I have stock coil but I think I burn it by unplug all 4 wires at the same time to check the compression. I read on the forum: Do not try to crank if your wires and spark plugs are not grounded... Now how can I check if my coils are good?

Or I just received my accel coils. I'm not sure if I should to find my problem with my old coils (if it's good) or use my accel...

Does I need to upgrade regulator/rect...? If yes what is the good and cheap way?
I have so many thing to learn on this 30 old project...

If you do not have a manual, please get one, and save yourself many headaches. Go to www.ringler.us/xs1100/ and download one till you can get a hard copy. The hard copy will happily follow you out to the garage, and be content to live there, won't eat any hay, and will not complain when your greasy fingers get it dirty.

The coil check procedure is spelled out, with pictures, in the electrical chapter. It tells you to check the resistence through the primary and secondary sides of the coil. The primary side, (the low voltage side), should be 1.5 ohms +/- 10%, and the secondary, (the high voltage side), should be 15,000 (15K) ohms. Anything more than 10% plus or minus outside these figures should be considered suspect. If you do not know how to use an ohm meter, (VOM), now would be a good time to get one and learn. It will be a necessary ability if you want to work on these bikes to any extent. If you have one and know how to use it, never mind.

If your old coils are good, by all means use them to get the rest of the system right. Then you know if the new coils are dead on arrival. (DOA)

There is no cheap way to replace the regulator, but member Geezer sells a replacement that is way better than any original, and probably not that much more expensive when you count the aggravation and postage costs of a DOA regulator off of e-bay. (Some of those sellers don't know what regulator model they have, let alone knowing if it works)
And again, the manual tells you how to check the one you have for servicable condition, using a VOM.

Good luck, CZ

[le_bucheron]

50 hr later va chier side stand relay!!!!

I found my fire problem! It was not easy because the motor can crank if you side stand relay is bad... thanks at all of you for your help!

[TopCatGr58]

Here is some good news for you. The TCI does NOT need 10.5 volts to operate. It will happily do its deed on 7 volts. The coils, however, are a different kettle of fish. As the input voltage goes down, the output voltage goes down, and at some point, there is not enough output voltage to jump the plug gaps.

Hey there CZ,

This is the FIRST time I've seen anybody post a contradiction to the "assumed" info of the TCI requiring 10.5+ volts to function properly. I do not know/remember who first posted it, whether they were an electronics GURU....ie. Randy/Davinci, or what? But I want to discuss this a bit more.

I tried reviewing the wiring diagram we have from the Clymer's for my bike, and 81SH, but the diagram is WRONG..it combines the 80 and 81 specials, and I KNOW that the 81 doesn't require/use a ballast resistor. I was trying to follow the diagram to see where the ignition coils get their power. Not sure if it's part of the Ignition fused circuit, or separate. I know on the earlier models, the power is first provided by the TCI to bypass the Ballast Resistor to provide the full 12 volts for stronger easier starting, but then routes it thru the BR after running. But the 81 gets full 12 volts all the time.

I experienced the LOW VOLTAGE no start problem this past spring when I had let my battery's cells get partially dry! IT would crank the engine, but would not start the bike. I have Dynatek coils which put out over twice the KVs of the OEM. SO...even at 10 volts, I would "THINK" that they would be able to put out more KVs than the OEM and enough to still jump the gap.

I put a booster battery onto my ignition fuse connector so that I could be assured that at least the ignition circuit was getting 12 volts despite what was running thru the rest of the harness...and sure enough the bike started!

But like I said, I don't know IF the ignition circuit provides the power for the ignition coils as well as the TCI or not...so the booster battery could have also jumped the voltage for the coils as well.

SO...I'm asking how you know that the TCI will work with less than 10.5 volts? I understand the principles of what you're saying about the ignition coils...but when the earlier bikes are running, the power to the coils is actually LESS than 10.5 volts...at least that's what I've been told when it's running thru the 1.5 ohm resistor..I don't know and haven't looked up the proper electrical formula for determining how many volts a 12 volt line will have after going thru a 1.5 ohm resistor...but have read that it's about 9 volts....well below the 10.5 volts you state that they will NOT fire if running on?

T.C.

[TopCatGr58]

A few more thoughts

Hey again,

Okay, I've done some research and trying to learn and understand Ohm's Law and such.

Okay, the TCI which handles the triggering of the coils...being on the negative/receiving side of the circuit....requires a total of 3 ohms for that circuit. According to the law, that should then say that the TCI draws about 4 amps....12 volts across 3 ohms of resistance.

So...let's say that the current has to be 4 amps. That current thru 1.5 ohms for the BR =6 volts...and another 1.5 ohms for the early coils = another 6 volts which equals the total voltage on the circuit of 12V.

So....now with the the later TCI design that needs 3 ohms on the coil trigger/neg side to keep the same 4 amps thru the TCI so it uses a coil rated at 3 ohms on a 12 volt supply which yields the required 4 amps.

The early model coils seem to be designed to run/fire on ~6 volts...and with the BR bypassed, they get the full system/harness voltage during startup...
so...if the battery is weak ie. 10 volts....during startup the coils should still see 10 volts at startup...which is 4 volts more than their normal running voltage of 6 volts....so they should still fire!?

However, at 10.5V or below, it's been reported by many members that their coils are not firing....but in theory they should still fire with just 10 volts....but they are not being triggered because the TCI seems to not be working at the less than 10.5 volts level!

Again, I'm no electronics guru, but this is my reasoning......so I welcome an alternative explanation.

T.C.

[crazy steve]

Yeah, I've seen the '10.5 volt' number mentioned a bunch of times, but can't find any documentation to back that up. Not saying it isn't true...

But there is confusion on where the coils get their power. The coils are fed the 12 volt positive power directly from the ignition circuit; the same circuit that feeds the TCI, but before/independent of it. The TCI supplies the grounding of the coils (completing the circuit), so the actual voltage to the coils could be different from what the TCI gets. Even the 'bypass' of the ballast resistor is independent of the TCI power, with the coil power simply 'passing though' the TCI (with a diode to prevent backfeed into the solenoid).

So even if the TCI is removed from the bike, you should still have battery voltage power measured to chassis ground at the R/W wire at the coils (if you have a '81 bike) or a lower number (whatever the ballast resistor drops it to on the '78-80 bikes). Bypassing the resistor on the early bikes, you should see battery voltage.

[CaptonZap]

Hey there CZ,

I put a booster battery onto my ignition fuse connector so that I could be assured that at least the ignition circuit was getting 12 volts despite what was running thru the rest of the harness...and sure enough the bike started!

But like I said, I don't know IF the ignition circuit provides the power for the ignition coils as well as the TCI or not...so the booster battery could have also jumped the voltage for the coils as well.

SO...I'm asking how you know that the TCI will work with less than 10.5 volts? I understand the principles of what you're saying about the ignition coils...but when the earlier bikes are running, the power to the coils is actually LESS than 10.5 volts...at least that's what I've been told when it's running thru the 1.5 ohm resistor..I don't know and haven't looked up the proper electrical formula for determining how many volts a 12 volt line will have after going thru a 1.5 ohm resistor...but have read that it's about 9 volts....well below the 10.5 volts you state that they will NOT fire if running on?

T.C.

Howdy T.C.

First of all, a disclaimer. My only area of interest is the 78-80 TCI, the 2H7 variant.
My explanation here is based on the wiring of the 80 G model, http://farm5.static.flickr.com/4054/...1ae5cbd4_o.gif
When the ignition is turned on, power is supplied through the fuse block, through the handlebar switch, (on/off), to the ballast resister, and to the TCI. This power is constant until the kill switch or ignition is turned off. (The tilt switch grounds the TCI circuitry through the B/W wire, and stops the ignition process, but leaves the current going through the TCI.)
As you surmised, putting the jumper to the ignition fuse sends the jumped voltage to both the TCI and coils. (R/W wire) When the starter solenoid is engaged, the power from the starter terminal on the solenoid is routed through the R/Y wire to a diode in the TCI, so that full battery voltage is run to the coils through the W/R wire. As soon as the solenoid disengages, power through the R/Y and W/R is stopped, and the diode keeps current from the still energized R/W wire to the coils from back feeding to the starter, which, if allowed to happen, would try to run the starter until the XSsive current draw through the ignition fuse blew it open. Don't worry, that is a BIG diode, and they are reliable.
While investigating the mysteries of the TCI, the 1156 bulbs that I use as a load, (they draw about the same current through a 1.5 ohm resister as the coils,) were getting dim. The battery feeding them and the TCI was low on voltage. Being curious, I continued to run the test machine until the voltage got down to 9.5 volts, at which time, not wanting to hurt the battery any more than I had, I quit. And all that time, the TCI did it's deed without complaint.
Since my observations went contra to prevailing wisdom, I figured that I might as well investigate the limits of the TCI, as regards input voltage.

Let me stop here and explain the current flow through the coils and TCI. The TCI draws 20-40 milliamps internally, and the coils draw roughly 4 amps, both drawing from the R/W wire. The current flow in the coil circuit goes from the R/W wire, through the ballast resister (no starter engaged) through the coils, to the TCI, and is grounded/interrupted by the TCI, on signals from the pickup (PU) coils. (The TCI acts as a set of points, if you know how they work in the Kettering ignition.)
My test rig can be set up to feed power to the TCI separately from the coil circuit, so I fed power from a variable voltage power supply, ( a battery charger powered through a router speed control, which is pulse width modulated, I think,) to the TCI, and battery voltage, (recharged) to the coil circuit. I started the PU drive, about 6000 RPM, and checked the operation of the TCI, to make sure that it was operating normally. I then started reducing the voltage to the TCI, and watched the lamps. They continued to shine, and when I got down to 4.5 V input, I interrupted the PU circuit on 1&2 cylinders. The TCI continued to function for about 5 seconds, and then shut down, as is it's wont. I then completed the PU circuit for 1&2, and the lamps lit back up.
I then slowed the reluctor rotation down to about 900 RPM, and the TCI still functioned normally. I then stopped the reluctor drive, and the lamps went out after about five seconds, which is normal.
I then started the reluctor drive, and found that at around that voltage, 4.5 V, the start up was sporadic, but at about 5 volts TCI input, it started every time.

I think that the "Don't let your battery voltage get lower than 10.5" is a good admonition, but as I pointed out, if you are in dire straights, there is a way to get a few more miles out of the battery.
(A couple of 6V lantern batteries wired to strategic places, duct taped to the sissy bar, made out of re-bar, springs diabolically to mind, like something out of a Mad Max movie. )
Questions? I'll tell you what I observed.
When the weather improves, I will verify some of the voltage readings on a real live coil system. (The 79 F.)

And that concludes this evenings broadcast from the Shock Locker. CZ

[TopCatGr58]

Yeah, I've seen the '10.5 volt' number mentioned a bunch of times, but can't find any documentation to back that up. Not saying it isn't true...

Hey there Steve,

I did a search on the site using "TCI 10.5 volts" as well as "TCI volts" and the earliest thread I could find was March, 2004 despite that the site has been up since 2002. The second search did show a few threads from 03. Part of the search criteria is that the search "word" has to have at least 3 letters in it. I'll try again with just TCI and see how far back it will go!

Surprisingly it was MY reply in the '04 thread and I was stating the 10.5 volts limit even then! But I can't remember where I saw it originally, and the search function was set to show ALL DATES. I know we did a site upgrade, and I remember the site being hacked many years ago, and so we might have lost the threads pre '04 ?

CZ, thanks for the explanation, I had forgotten about your test rig you had mentioned before! So...according to your test results, the TCI will work as low as 5 volts. Even though sparks can be seen on an exposed plug, we know that it takes more energy to get it to jump the gap under pressure/load, and so the actual real world minimum voltage for both the older 78-80 oem coils as well as the newer 3 ohm units would be nice to find out. But according to your data, the TCI should remain functional down to a fairly low volt level, so you may be right afterall that when the system voltage drops low enough that it's the actual ignition coils that stop firing due to not being able to generate a strong enough primary coil field to create the required strong enough secondary field current to make a usable spark!

Great discussion indeed!

T.C.

[TopCatGr58]

Followup research

Okay, a little more searching revealed a few more clues.

First is this tech tip:

http://www.xs11.com/forum/showthread.php?threadid=769

Mike Hart states the TCI requires 11.7...or at least the battery voltage needs to be at or above that.

Then in 2/03 one of our veterans SKIDS posted in this thread:

http://www.xs11.com/forum/showpost.php?p=9367&postcount=2

stating that 10.2 volts or so was needed by the TCI. I don't know where he got that info, he's still on the site from time to time, think I'll drop him a PM and ask him!

I found these by reviewing the threads from the BEGINNING, and after checking some 50 pages...that's what I could find!

T.C.

[crazy steve]

..Mike Hart states the TCI requires 11.7...or at least the battery voltage needs to be at or above that..

Mike Hart's tip has at least one error in it; voltage measured at the coil side of the ballast resistor will be less than battery voltage. The number you see will also depend on how close the actual resistance is to the 1.5 ohm spec. I'll also note that if you check this voltage while the bike is running, you'll get an entirely different number because of the changing impedance of the coil(s).

I think what we're seeing here is various numbers that people have measured when their ignition didn't work. Depending on whatever other issues were going on, you could have a pretty wide range of 'fail' voltages....

[MaximPhil]

While you guys are trying to figure it out:
Electrickety remains PFM (Pure F**king Magic) to me.
(Thanks to Rasputin for the new word)
Phil

[skids]

I think what we're seeing here is various numbers that people have measured when their ignition didn't work. Depending on whatever other issues were going on, you could have a pretty wide range of 'fail' voltages....

You hit the nail on the head for my comment on this site made years ago. My ignition was failing (no apparent spark) and at the same time my battery was down to 10.2 volts or so. To me, I couldn't imagine what else it could have been except for low voltage to the black box. New battery gave new life.

[CaptonZap]

After a nice afternoon with warm weather, I have more info.

I popped the top of the 2H7 on the 79F, and measured the voltage to the collectors of the switching transistors (these are the terminals that have the current from the coils running to them, and break the circuit when spark is needed.) I got the following readings.
With the ignition on, engine not running, the battery voltage was 12.09, at the battery side terminal of the solenoid.
At the collectors of the transistors, 11.11V, 11.09V. ( Looks like I need to clean some connectors, since that is the voltage getting through the switch, wiring, etc, to the coils. )
With the engine running, 20 V DC scale, idle RPMs, reading were 8.8, 9.4 V, respectivly. This was at 3000 RPM. At idle speed, the voltage rose to 11+/-.
Revving the engine changed the reading by a couple of volts +/-.
Switching to 20V AC range, I got appx 5V at idle, rising to appx 7 V at 3500 RPM. (Poor little meter was confused with the pulsating DC. )
I used a Centech Mod # P37772 meter. (Yeah Steve, I can hear you snickering. But then, this isn't rocket science. )
So it would seem that 2 to 3 V DC drop across the coils and resister is a reasonable assumption.
I will have to pop the tank and measure the current through the wire feeding the coils.

Well, that didn't go well. The meter didn't like the pulsating DC while in the DC amp mode, and I couldn't get a stable reading of the amp draw.
So I measured the ohms through the BR and coils, and came up with 3.4 ohms each side. Close enough.
Mr Ohm says that the current was 3.2 amps, which sound reasonable. Since only one coil draws curent at a time, (depending on dwell time), I would guess that the total draw for both coils is not much different than that.
He also says that the voltage drop across the 3.4 ohms amd 3.2 amps is 10.88 V. Stands to reason, 'cause when the transister conducts, it has to drop all the voltage to ground. ( I assume there is an additional collector/emmiter drop across the transistor, but I'm not sure.)

But here is the interesting part.
I put the digital scope on the collecter terminal, and saw the wave form of the current through the transister.
When the transister opened there was a spike in the voltage, which peaked at 44.6 volts, dropped down to 35volts for about 750 microsec, spiked again, then dropped to 0 V, and rose to about 11 V, held that for about 20 milliseconds, and then dropped down to 0 V after another 20 milliseconds. That last 20 msec equates with dwell time, the way I see it.
The average voltage over the cycle was 9.17 volts, which tallies with the DC volt reading that I got when I measured at the C terminal of the switching transister.
The voltage spikes are the inductive "kick" that the coils induce.
So my guess is that 9 volts is the coil feed voltage, and if you fed them that without the BR, they should operate normally. Someday I may try.
Anybody want to give me a clearer picture of what is happening ? I wish Cy Welch was still around.

Confusion reigns, CZ

[crazy steve]

Anybody want to give me a clearer picture of what is happening ?

CZ, you're seeing the effects of reactance. Several things going on here; first, the 'spikes' you're seeing are from EMF (electromotive force) generated by the building/collapsing of the magnetic field as power is applied/removed from the coil windings. This is inductive reactance. You're also seeing a 'echo' of the capacitive reactance of the spark plugs (the spark gap is a form of capacitor), although I would think that's a small part of the total.

The other thing to note is the coil primary 'resistance' isn't a 'set' value. If you measure it with an ohmmeter (no power applied, the ignition not operating) you'll get a 'static', resistance-only value, but once in operation the effects of reactance will change the 'resistance'. This is actually 'impedance', which is a vector sum of the resistance and reactances involved, also measured in ohms. Frequency, or how many times the circuit is switched on/off in a given time frame will change the reactance values, so the impedance of the coil will change according to motor RPM. As frequency goes up, inductive reactance goes up also, increasing the impedance ('resistance') and the amount of voltage dropped across the coil. The higher total circuit impedance also reduces the total current in the circuit.

This is why those small 'mini-coils' that Dyna sells won't work on the XS ignition system. At low RPMs, the coil impedance gets too low and the current flow though them will burn them up. The 'dwell control' that later ignitions have limits the amount of time power is applied at low speeds, preventing maximum current.

This make it any clearer?....

[CaptonZap]

This make it any clearer?....

Well, I think so.
What I don't understand is the second high spike before the voltage drop.
If I sent you a picture of the scope trace, could you give me a play by play interperatation?
If anybody else wants a copy, let me know.

Rats, nice weather, and the Super Bowl.
Decisions, decisions.

Thanks, Steve

CZ