No sparks = no go

[crazy steve]

Uhhh... Pete, better study up on electrical theory. The TCI box is what switches power on and off to the coils, and seeing how the ballast resistor is the other, 'common' side of that circuit, controls the coil current draw. That's why it's there...

[Rasputin]

Now see what I started.
I piped in with wrong (backwards) info. Once corrected, I thought that maybe it would still provide 12 volts to the coils if there was a flaw in the starting circuit. Which I thought may be a possibility due to the starter not working correctly as well as no spark. The thought was to disconnect it and give it a try to see if there was any change in the spark, then reconnect it.
Sometimes things get lost between my brain and the keyboard. I did not want to derail or hijack this thread and I apologize. I must say however that I am learning things from this, and hope something helps get Lo-Ho's spark back.

[petejw]

hi steve,
if thats the case in what ur saying then any1 who
has updated there coils and have bypassed the b/r
then there tci would be burning out because of the increased voltage?

the tci gets its pulses ("power on and off to the coils") from the
pick ups not the b/r.

the ballast resistor comes into play when the engine is
running to supply lower voltages to the coils only, in a car
it was around 9 volts(not sure on our bikes)
when the engine is cranking the b/r is then bypassed
supplying 12 volts to the coil.

the b/r isnt in circuit with the tci, the b/r are the red and
white coloured wires that go to the + coil and the blue and orange
wires (- coil) are the ones that run from the pick ups and tci.
the tci has power going to it buts its not supplied thru the b/r. .

ill see if i can find a electrical diagram.

[petejw]

hi rasputin,
it would show up if u had a faulty b/r
but u would have to join the wires together to test,
and not leave it an open circuit.

doing this tho ur putting ur coils at risk of burning out,
receiving full voltage all the time,
one of those things that could happen the first time u try it
or never at all.


nothing wrong with a good discusion.

[Rasputin]

Have you tried removing the ballast resistor and connecting the two leads together to see if you have spark while cranking?

Hey Pete.
I knew about connecting the two leads together. I was just thinking that if this was something that was not going to work, then maybe we should get back to Lo-Ho's original problem.
I like reading discussions for sure as that is one way for me to learn more. It just is not solving the original problem in this case. Of course who knows if it may trigger some thoughts on what is really wrong, from someone reading it.

[crazy steve]

hi steve,
if thats the case in what ur saying then any1 who
has updated there coils and have bypassed the b/r
then there tci would be burning out because of the increased voltage?

The 'updated' coils have a higher 3 ohm resistance, so they don't need the ballast resistors. The stock bikes with the resistors have 1.5 ohm coils which will draw roughly 8 amps at 12 volts. Add in the 1.5 ohm resistors in series, and now total circuit resistance is 3 ohms; reducing the current to 4 amps, which is what the TCI can handle on a continuous basis. It can only take the 8 amp load for a short time before it overheats and fails.

You've got the function of a ballast resistor backwards; it's removed from the circuit (allowing the full 12 volts to the coil for a hotter spark) during starting only; once the starter button is released, the resistor is switched back into the circuit and drops the voltage/current down.

You're right, the pickups send their signal to the TCI, but the TCI uses the signal to electronically switch the power on and off to the coils.

[petejw]

"You've got the function of a ballast resistor backwards; it's removed from the circuit (allowing the full 12 volts to the coil for a hotter spark) during starting only; once the starter button is released, the resistor is switched back into the circuit and drops the voltage/current down."

ive always said that, i agree with u there,
but here

"You're right, the pickups send their signal to the TCI, but the TCI uses the signal to electronically switch the power on and off to the coils."

it does that with the blue/ orange wires going to the neg coil,
not the positive red/white wires going to the positive side of the coil
which the balast resistor is in line with.
the tci gets its power from the kill switch
not from the ballast resistor.

[crazy steve]

it does that with the blue/orange wires going to the neg coil, not the positive red/white wires going to the positive side of the coil which the balast resistor is in line with. the tci gets its power from the kill switch not from the ballast resistor.

Pete, an electrical circuit is a loop; it has to be to work. Wherever the power starts from, it goes out the wire, through the various components, and comes back to where it started. Any component in that circuit affects the whole circuit...

[petejw]

im not arguing with your theory,
but its not part of the 'loop'
your refering to, the best way i could put it
would be to disconnect the b/r without joining the wires,(open circuit)
you would still get 12 volts to the tci but you wouldnt be getting
12 volts to the coils, according to your theory, the loop would be
broken and the tci wouldnt be getting any voltage.

[DAVINCI]

pete, steve's got it right. Anyway, loho, no need to do any re-wiring, just holding the starter button cuts the ballast resistor out of the loop

[James England]

The 'updated' coils have a higher 3 ohm resistance, so they don't need the ballast resistors. The stock bikes with the resistors have 1.5 ohm coils which will draw roughly 8 amps at 12 volts. Add in the 1.5 ohm resistors in series, and now total circuit resistance is 3 ohms; reducing the current to 4 amps, which is what the TCI can handle on a continuous basis. It can only take the 8 amp load for a short time before it overheats and fails.

So, just to confirm (because I want to put 3 ohm coils in).. On the standard setup, the coils are 1.5 ohm. This lower resistance (compared to 3 ohm) allows the coils to draw 8 amps when the starter is pressed and this gives a better spark while the button is pressed (or 'depressed', as they say in the manuals... sounds sad). Then, when the starter button is released, the ballast resistor kicks in and lowers the amps drawn down to 4 amps. The TCI can handle a short burst of 8 amps going through it whilst the bike is being started but wouldn't be very happy if it had 8amps going through it all the time. So... BAD idea to bypass the ballast resistor when standard coils are fitted as the system will be handling double the amps is supposed to when the engine is running. But, when 3 ohm coils are fitted, they draw only 4 amps (because of their higher resistance) and the ballast resistor can safely be bypassed by joining the terminals together on the wiring loom.

Correct???

[natemoen]

Correct James.

[soccer4m]

Tried a different TCI, ignition box????

Now that all the electrical theory is done,,,,,hey LoHo, do you have an extra ignition box, tci, to plug in and see if that will give you the correct spark?? If not, they are pretty cheap.............let us know, this spark problem has quite a few of us mentally involved....................Mike in Sun DIego

[DiverRay]

LoHo,
If you need KNOWN GOOD spares, let me know. I can meet you half way and you can have them today!. I DO have most of the electrical tested here, as you may be aware of.

[crazy steve]

It really spounds like LoHo has a bad TCI or bad connections between the TCI and the pickup coils; but if his TCI has failed, it's done so with the switching function to the coils closed, rather than open like they typically do. So when power is applied, the coils saturate fully and when he turn the key off, they discharge with a nice big fat spark producing the backfire.

One other thing that hasn't been mentioned and could possibly cause this problem; the gap between the reluctor and the pickup coils. Too big a gap, and the pickup coils won't see enough of a signal to trigger the TCI (or an intermittent signal). I've never had mine off the backplate so I don't know if there's any adjustment for these or not. I looked in vain for a recommended gap in the manuals...

The flaw in this theory is if the TCI isn't getting a signal from the pickup coils, it's supposed to shut itself off to prevent damage, which should prevent the backfire. So that brings you back to it being a bad TCI..