No spark first several kicks

chrispix · Jul 3, 2016

I have a '75 Commando that starts easily with the electric start on a full charge. Boyer ignition, Mikuni carb. However, when it sits for a few days, I get no spark the first several (15 or so) kicks or tries with the starter. Invariably I pull out a plug to check for spark, and it starts sparking soon after that, which I assume is coincidental. Once it's running, it'll spark and start again the first try.

Is there something in the ignition system that could need a warm-up like this if it's failing? Maybe coils? I've looked up some guides on testing the ignition system, but I'm frankly a numbskull when it comes to electronics and I don't understand half of what I'm reading.

acotrel · Jul 3, 2016

Whenever I return from a practice session and put the bike in the shed, I remove the jet covers from the bottom of the carbs and put them on the shelf for a while to make sure there is no methanol remaining in the float bowls. Usually when I go to start the bike again after refitting the jet covers, it starts instantly. The last time I took the bike to Winton, for the first time ever, it totally refused to fire until I replaced the plugs. I suspect that sometimes the carbon which remains on the plugs after you stop the motor, can get into a condition where it conducts electricity

Danno · Jul 3, 2016

The older Boyers are sensitive to low voltage, so perhaps your starter is pulling the battery voltage down below the minimum requirement and as the capacitor (blue can) takes a charge and discharges, line voltage rises to the point of making the Boyer function as it should. Just a wild guess. How old is the battery?

kerinorton · Jul 3, 2016

Fit a Pazon.

maylar · Jul 4, 2016

Try a new pair of spark plugs.

jaydee75 · Jul 4, 2016

Next time you try it cold, take the plugs out first and see if they spark immediately or after 15 kicks. Then you'll know something.
Jaydee

chrispix · Jul 7, 2016

Danno said:
The older Boyers are sensitive to low voltage, so perhaps your starter is pulling the battery voltage down below the minimum requirement and as the capacitor (blue can) takes a charge and discharges, line voltage rises to the point of making the Boyer function as it should. Just a wild guess. How old is the battery?

The battery is about a year old, kept on a trickle charger. I think it's in good shape. I did try disconnecting the capacitor, which seemed to help at first, but hasn't resolved the problem.

kerinorton said:
Fit a Pazon.

Someone else gave me this advice yesterday. Apparently they handle voltage dips better than the Boyer? Wondering if that might be a better step before trying new coils.

maylar said:
Try a new pair of spark plugs.

The plugs are pretty new, but I think I'll try replacing one and pulling both when it's cold to see if the new one sparks.

Nater_Potater · Jul 7, 2016

chrispix said:
Invariably I pull out a plug to check for spark, and it starts sparking soon after that, which I assume is coincidental.

How soon after? Does it not spark from the first try once it's laying out on the head?

chrispix said:
kerinorton said:

Fit a Pazon.

Click to expand...

Someone else gave me this advice yesterday. Apparently they handle voltage dips better than the Boyer? Wondering if that might be a better step before trying new coils.

'Can't speak on the low voltage capabilities, but the Pazon Altair has been one of the better additions to my '74. The idle stabilization is great!

Nathan

L.A.B. · Jul 7, 2016

chrispix said:
However, when it sits for a few days, I get no spark the first several (15 or so) kicks or tries with the starter.

Have you checked for power at the Boyer box when you are getting no spark?

Bad contacts at the kill switch or the multi-pin connectors could possibly be causing or contributing to the problem.

chrispix · Jul 7, 2016

Nater_Potater said:
How soon after? Does it not spark from the first try once it's laying out on the head?

Depends. Sometimes first try once the plug is out, sometimes only after several tries.

chrispix · Jul 7, 2016

L.A.B. said:
Have you checked for power at the Boyer box when you are getting no spark?

Bad contacts at the kill switch or the multi-pin connectors could possibly be causing or contributing to the problem.

I'll check that. I do have a wonky kill switch, and I ended up wiring it to the ignition light so I can see when the switch is actually closed.

L.A.B. · Jul 7, 2016

chrispix said:
L.A.B. said:

Have you checked for power at the Boyer box when you are getting no spark?

Bad contacts at the kill switch or the multi-pin connectors could possibly be causing or contributing to the problem.

Click to expand...

I'll check that. I do have a wonky kill switch, and I ended up wiring it to the ignition light so I can see when the switch is actually closed.

For standard positive earth/ground. I suggest you try running a temporary wire from the battery negative terminal to the Boyer box white and see if that improves matters? If it does, then it's likely there is a bad connection somewhere in the power supply to the Boyer.
If it doesn't make a difference, then try running a temporary wire from battery positive to Boyer box red and/or the coil "2" positive connection.

Deets55 · Jul 7, 2016

FWIW

Jeander (spl?) made an interesting statement in one of his posts. He said that if you wait too long from when you turn on the ignition and then attempt to start the engine that the Boyer will shut off to prevent an overheat situation. Not saying this is your initial problem but it might be part of your problem. Something to consider.

Pete

o0norton0o · Jul 7, 2016

L.A.B. said:
chrispix said:

However, when it sits for a few days, I get no spark the first several (15 or so) kicks or tries with the starter.

Click to expand...

Have you checked for power at the Boyer box when you are getting no spark?

Bad contacts at the kill switch or the multi-pin connectors could possibly be causing or contributing to the problem.

Cruddy or worn out old ingnition switch contacts can make an ignition intermittently act up also. If your key switch is the original, then it might be prudent to replace it....

maylar · Jul 8, 2016

Deets55 said:
FWIW

Jeander (spl?) made an interesting statement in one of his posts. He said that if you wait too long from when you turn on the ignition and then attempt to start the engine that the Boyer will shut off to prevent an overheat situation. Not saying this is your initial problem but it might be part of your problem. Something to consider.

Pete

When ignition is turned on, the Boyer "charges" the coils in anticipation of the first kick. I think this was intended to make starting easier. If you don't kick within a second or two, the Boyer goes into standby mode to conserve battery power, but it will respond to pulses from the pickup regardless.

chrispix · Jul 31, 2016

L.A.B. said:
For standard positive earth/ground. I suggest you try running a temporary wire from the battery negative terminal to the Boyer box white and see if that improves matters? If it does, then it's likely there is a bad connection somewhere in the power supply to the Boyer.
If it doesn't make a difference, then try running a temporary wire from battery positive to Boyer box red and/or the coil "2" positive connection.

Was interrupted for a while by house shopping and vacations. Today I tried both jumper wires as you suggested and did not get a spark with either.

chrispix · Jul 31, 2016

I also tried disconnecting the stator plate leads from the boyer and connecting the blk/yl and blk/wh wires with the plugs out on the head, which as I understand it should cause the plugs to spark. I did not get a spark.

chrispix · Jul 31, 2016

...and then I busted a spark plug wire lead at the coil trying to check its fit. So I'll be ordering new wires before I can get any further. Thinking about getting a new set of coils at the same time.

No spark first several kicks

chrispix

acotrel

Danno

kerinorton

maylar

jaydee75

chrispix

Nater_Potater

L.A.B.

Moderator

chrispix

chrispix

L.A.B.

Moderator

Deets55

o0norton0o

maylar

chrispix

chrispix

chrispix

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