Topic: Pop quiz-Why would 1 and 4 suddenly lose spark?

[Freebirdbeachbum]

Hints: it’s not the coil, the points or condenser. There is power to the coil and continuity on the blue wire from the breaker to the coil.

Is there a ground to check that I’m missing?

[Deltarider]

If you're sure about the points and its condenser, I'd unscrew the sparkplugs and have a look. Plugs can have gone bad, so can the plugcaps and their connection.

[flybackwards]

Since one and four come from the same coil - that would be my pick for more diagnosis - voltage at the coil does not mean the coil is working - check coil connections carefully and check the coil with a meter for continuity.

[Bodi]

There is no ground except through the points. The coil output is double ended, one end to 1 and the other to 4.
Confirm battery power to the coil, unplug the colored wire to the points at the coil. Remove one spark plug and set it on the engine or at least touching metal somewhere with the cable connected to it. Use a test lead, connect one end to the coil end of the colored wire and touch the other end to the engine or frame, then lift it off. When you lift it off the plug should spark. If it does, the points or wiring is bad (or the condensor has gone short). If it doesn't and you're sure the coil has power, the coil is bad or the spark is happening through the plug wire to ground somewhere it shouldn't.

[madmtnmotors]

Hints: it’s not   EITHER the coil, the points, condenser, or anything in between (i.e wiring).

FTFY 

Unless you somehow sheared off both ends of the cam simultaneously... 

Power to the coil and continuity on the blue wire rules out nothing other than that there is power to the coil and there is no break in the blue wire. Put power to a failed coil and it is still a failed coil.

[Freebirdbeachbum]

Hints: it’s not   EITHER the coil, the points, condenser, or anything in between (i.e wiring).

FTFY 

Unless you somehow sheared off both ends of the cam simultaneously... 

Power to the coil and continuity on the blue wire rules out nothing other than that there is power to the coil and there is no break in the blue wire. Put power to a failed coil and it is still a failed coil.

I knew it wasn’t the coil because I replaced the coils to rule out the coils as the problem.

[bryanj]

 If it aint the coil it has to be points or condenser.
.
Try diconnecting the appropriate wire in rubber boot by rear brake switch and momentarily ground it with ignition on, you should get a spark from small wire as you ground it and a spark from ht as you disconnect it again

[Maltboy]

I'm no expert, but aren't non-OEM condensers notoriously unreliable? 

[Deltarider]

If you're sure about the points and its condenser...

I've began my reply with this ^, because my thought was: must be the points or the condenser. Well, the condensers 1+4 and 2+3 are identical and hence easily swapped to rule out a defective one. It's done in two minutes.
A quick method to test the ignition, is to slide a thin piece of plastic - or whatever may isolate - in between the points and then attach a small simple test wire with an alligator clip to the tiny bolt of the breakerpoints. With the other end of the wire you can make ground as often as you like, without having to turn the crank. Warning: the first contact may cause a bang in the exhaust when it ignites some leftover mixture.
What Bryan suggests, is also possible but once the condenser is not in the circuit, grounding will result in a very weak spark at the HT side.

[madmtnmotors]

I knew it wasn’t the coil because I replaced the coils to rule out the coils as the problem.

It would be good to include that little nugget of information up front rather than relying on our keen powers of intuition...

My focus would turn to points/condensers/ and their associated wiring then. "Sudden" failure of both 1 and 4 "points" to this.

[Freebirdbeachbum]

I knew it wasn’t the coil because I replaced the coils to rule out the coils as the problem.

It would be good to include that little nugget of information up front rather than relying on our keen powers of intuition...

My focus would turn to points/condensers/ and their associated wiring then. "Sudden" failure of both 1 and 4 "points" to this.

I did include that info in my initial post to be fair.

[bryanj]

Just cos parts are new doesnt mean they work.
You need to start at the begining and check for power all the way from battery to each coil then at eack points wire, if thats all ok you should get a spark at ht lead, no cap or plug fitted, if not you have a coil short which i have only seen once in 40 yrs and it wasnt a honda

[Freebirdbeachbum]

Just cos parts are new doesnt mean they work.

Sorry. To clarify. In an effort to rule out certain causes of this issue that suddenly arose, I replaced the existing coils, caps, points and condensers with new parts.

[bryanj]

But any one or any combination of those "new" parts may by duff

Like i said, start from the battery and verify voltage all the way through

[Freebirdbeachbum]

But any one or any combination of those "new" parts may by duff

Possible but unlikely both the old and new were bad.

Initially, I replaced just the left side condenser and that didn’t do it so I replaced the coils, caps, points and right side condenser since I had them available.  None of that worked.

While replacing the left side points, I noticed the condenser connector may have been touching the plate and moved it. 1-4 are now getting spark but since I also did those other things I can’t be certain it was the condenser connector. Would that have done it?

[bryanj]

Yes, its the most common problem

[madmtnmotors]

I knew it wasn’t the coil because I replaced the coils to rule out the coils as the problem.

It would be good to include that little nugget of information up front rather than relying on our keen powers of intuition...

My focus would turn to points/condensers/ and their associated wiring then. "Sudden" failure of both 1 and 4 "points" to this.

I did include that info in my initial post to be fair.

Your initial post? In a different thread? Sorry, I didn't see your "initial" post.

Shorting the condenser to ground will definitely kill the spark.

[seanbarney41]

Can we see a nice clear picture of your new points and condensors?

[Deltarider]

While replacing the left side points, I noticed the condenser connector may have been touching the plate and moved it. 1-4 are now getting spark but since I also did those other things I can’t be certain it was the condenser connector. Would that have done it?

Yep, that's often the case, but it's mostly the 2+3 connector. 

[Freebirdbeachbum]

I did include that info in my initial post to be fair.

Your initial post? In a different thread? Sorry, I didn't see your "initial" post.

My initial post meaning the one that started this thread.

[madmtnmotors]

My initial post meaning the one that started this thread.

Hints: it’s not the coil, the points or condenser. There is power to the coil and continuity on the blue wire from the breaker to the coil.

Is there a ground to check that I’m missing?

Where does it say that you replaced the coils?

[Freebirdbeachbum]

My initial post meaning the one that started this thread.

Hints: it’s not the coil, the points or condenser. There is power to the coil and continuity on the blue wire from the breaker to the coil.

Is there a ground to check that I’m missing?

Where does it say that you replaced the coils?

It was one of the hints but perhaps too cryptic. My apologies.