Boyer sparks,... but not when engine turns over

Riddle me this....

`71 engine running hot and normal to/from home. Normally a 1-kick engine even cold. (Good))
Has a year/3,000 miles on this Mk-III Boyer with normal (fresh) wiring harness and positive ground (Good)
I get back to garage and it quits as I'm turning the ignition from away from the "Lights" position to the normal "On" position during shut down. (Uh Oh)
Won't restart. (Bad)

- Plugs now do not fire when pulled/laid against head and the engine kicked over. (Bad)

- Battery is new/freshly charged, 12.5V and easily passes the 1-minute headlights/stoplight load test (Good)
- Ground connection to headsteady/frame bolt is firm (Good)
- Connections to/from Boyer box/Coils/jumper between coils are rechecked (Good)
- Coils measure ~2+ Ohms each (Good)
- When disconnected, resistance across the white/black & yellow/black wires running to the Boyer timing plate measures 140 Ohms, with no effect upon wiggling (good)
- With the white/black & yellow/black wires disconnected and ignition switched 'ON', the plugs fire immediately (good?/bad?)
- Plugs will not fire when white/black & yellow/black wires to the Boyer Box are scratched together/apart to simulate timing plate trigger signal (bad?)
- With the white/black & yellow/black wires connected and ignition switched 'ON', the plugs fire after a slight/half-second delay upon coil buildup/discharge (??)
- With everything connected and after plugs fire upon switch 'ON', the plugs will fire again as kill switch is depressed (Good -- Kill Switch works/dumps coil to ground)

Sounds like Box problem...? (he asks)

Thoughts?

Sounds vaguely familiar...

Keyswitch contacts dirty.

I was going to go home tonight and bypass the ignition switch/run wiring directly
from the battery to the Boyer box:

BAT(-) To White lead

BAT(+) to Red lead

The only thing that gives me pause is that I (appear) to get assimilator light/ignition/coil action to
the plugs (spark) when the ignition is switched on. It just doesn't fire (at all) when kicked through.

the plugs (spark) when the ignition is switched on. It just doesn't fire (at all) when kicked through

Click to expand...

I'm sure that means there's a fault with the stator or it's wires.

Cash

...means there's a fault with the stator or it's wires....

Click to expand...

Possibly, though I ran the classic resistance check across the stator/timing plate leads and they read normal (140 Ohms)

Also... (were that the case) I was under the impression that "scratching" the powered-up box's stator leads together simulated the stator's timing signal and would therefore trigger the box to discharge the coil/spark -- but nothing happens.

Tis a puzzlement.

Touch the trigger wires together and no spark indicates bad box.

The box should normally not fire when switched on. This indicates that its either a problem with the box or the box is possibly for a Triumph/BSA. :?:

I was hesitant to email Boyer but they responded very quickly (within 24 hrs).

My thoughts exactly.

Great minds........... 8)

MEHAVEY said:

I was under the impression that "scratching" the powered-up box's stator leads together simulated the stator's timing signal and would therefore trigger the box to discharge the coil/spark -- but nothing happens.

Click to expand...

http://www.tioc.org/boyertest11.htm

With the spark plug laying on the cylinder head, Scratch the Black/Yellow and Black/White leads from the ignition control box on each other.
Please Note: This test ASSUMES the battery, wiring, connections, switches and grounds are in working order.
Although a lot is attributed by other web sites to this test, it is very possible for the box to be in perfect working condition and you will not see a spark at the plug.

Click to expand...

Note" Turning the ignition switch On and Off will fire the spark plug on most Boyer ignitions, it WILL NOT with the Triumph/BSA and Norton ignitions. The box does not turn on until it receives a trigger voltage from the timing plate.

Click to expand...

Note" Turning the ignition switch On and Off will fire the spark plug on most Boyer ignitions, it will NOT with the Triumph/BSA and Norton ignitions. The box does not turn on until it receives a trigger voltage from the timing plate.

Click to expand...

Exactly. My fully-connected Boyer box DOES trigger/dump the coil/fires the plugs about a 1/2 second after the ignition is switched "on".

MEHAVEY said:

Exactly. My fully-connected Boyer box DOES trigger/dump the coil/fires the plugs about a 1/2 second after the ignition is switched "on".

Click to expand...

So, are you sure you have the right Boyer box?

...you sure you have the right Boyer box?

Click to expand...

Roger that -- KIT00053 MKIV -- Micro MKIV Electronic ignition system for Norton Commando
http://www.boyerbransden.com/instructions.html

It's run fine for the last year/2,000 miles.
Weird (unless it really is a dead box)

My black box analog Boyers did fire on first key power up and by each key off or touching kill button. There is no difference TRI/BSA/nor analog Boyer, they are all built to serve the most detonation prone TRI, eek- lazy advance curve.
Your slow delay to fire ~.5 after power on implies coil or Boyer but if coils instant fire on other tests then better suspect you know what.

Hobot sez...

...but if coils instant fire on other tests then better suspect you know what.

Click to expand...

Plugs instant fire w/ trigger leads unplugged/ignition switched 'on' (as they should).
Delayed plug fire comes when trigger leads are reconnected/ignition switched 'on'

'What' it is :evil: ....

Jeandr wrote in the "other" Boyer string:

...why not put a meter on the output lead of the boyer (that is the lead that goes to the coil) and take a reading...

When switched on, what is the reading

Click to expand...

In my particular case the voltage on the Boyer's BLACK (output?) lead goes quickly from zero, ...to 12 volts, ...then immediately back to zero, ...and stays zero.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Jeandr also wrote in that "other" Boyer string:

There is another possibility, the coil is faulty. The way to test is to disconnect the wire going to the Boyer. Now turn on the ignition, use a clip and ground the side of the coil from which you took off the wire and see if you get a spark when you take the clip off,

Click to expand...

I'm not sure I understood what you meant from a circuit point of view. If I follow you correctly I should (1) disconnect the (black?) boyer lead going to the coil tab; and (2) ground that self-same coil tab (as shown below.) If I do that, I appear to have just grounded the whole coil setup. How would any charge collect to then fire the plug?

(Or have I got this whole thing bass-ackwards?)

Actual Boyee Switching Functioning

.
It might be handy to know the answer to the two questions below...

FOR A NORTON BOYER:
Question 1: Is a steady 12V supposed to appear at the the Boyer's BLACK lead going to the coils when ignition is "ON"?
Question 2: Is the Boyer supposed to dump the coils to ground across the RED lead when the stator/timing signal arrives?

swooshdave said:

Touch the trigger wires together and no spark indicates bad box.

Click to expand...

Or a bad points wire. You might want to substitute a short jumper wire for the points wire.

Not sure if touching the points wires together will trigger a spark with the KIT00053 MKIV -- Micro MKIV Electronic ignition system for Norton Commando, but it will with the Mk III analog unit.

Has the original poster tried connecting the black box straight to the battery yet?

-Eric

Re: Actual Boyee Switching Functioning

MEHAVEY said:

.
It might be handy to know the answer to the two questions below...

FOR A NORTON BOYER:
Question 1: Is a steady 12V supposed to appear at the the Boyer's BLACK lead going to the coils when ignition is "ON"?
Question 2: Is the Boyer supposed to dump the coils to ground across the RED lead when the stator/timing signal arrives?

Click to expand...

With the Mk III unit you definitely won't see a steady 12V on the negative wire going into the coil, it turns off in less than a second after it stops receiving a signal from the stator. You have to kick it over, or touch the black/yellow and black/white wires together to see voltage.

-Eric

Roger all..... (but that wasn't working either).

Sose I went down to my favorite find-everything Norton club President's garage and he came up with another Box.

With the new box jumpered in, it started first kick.

Not only does the bike now run, ...but two weeks of head-scratching, web searching, and point-by-point test ideas from the troops on this Forum has resulted in something even better happening: I now understand the whole ignition circuit/Boyer system.
:mrgreen:

MEHAVEY said:

Roger all..... (but that wasn't working either).

Sose I went down to my favorite find-everything Norton club President's garage and he came up with another Box.

With the new box jumpered in, it started first kick.

Not only does the bike now run, ...but two weeks of head-scratching, web searching, and point-by-point test ideas from the troops on this Forum has resulted in something even better happening: I now understand the whole ignition circuit/Boyer system.
:mrgreen:

Click to expand...

Well better than me. All I learned from all my head scratching is that I'm still a dumb-ass. :mrgreen: