Topic: No spark

[Bastaldo]

Hi there. I searched and couldn’t find this exact situation. 
I’ve got a 76 cb550 that spent some quality time with a builder.  When I got it back the electric was all messed up. For one, there was no power to the coils. I fixed that, and the coils are getting power and I static timed the electronic ignition. But still no spark. I tested both coils and they both read 1.1 ohms, so I have a feeling I may have tested them incorrectly. Is it possible that both coils (originals) got blown at the same time? What other issue could kill the spark between the ignition and the spark plug,
Thanks!

[bryanj]

Unlikely for both coils to blown simultaneously but a fractional second of incorrect connection would destory the electronic box

[Deltarider]

... I static timed the electronic ignition. But still no spark. I tested both coils and they both read 1.1 ohms

Bastaldo, you need to be more specific. What electronic ignition and what coils, genuine Honda or aftermarket? But 1,1 Ω is unusual low.

[Bastaldo]

bryanj- what do you mean by electrical box?

Deltarider- It's got genuine Honda- never changed- coils and plug boots/caps. The ignition is Dyna S.

When i got the bike back, some how, some way, the coils were wired through a hacked together harness. It fired fine, then 1,4 went out, then all went out. (at which point i discovered the hacked together harness had broken off and I never could figure out how it was originally wired).

At point point, I was able to get spark but then nothing after I rewired directly from the M unit to the coils (and electronic ignition). I used a test light to show that the coils and ignition were getting power (and checked the static time was correct).

[bryanj]

The electronic ignition control circuit mate

[Bastaldo]

bryanj- if it was shot, wouldn't that disallow the static timing test? (aka, it wouldn't work).

[Bastaldo]

calj737 - Bingo!

It's a 76 CB550. The Coils are original, the ignition is a Dyna S, the Batter is antigravity 12v, and it's kick only.

I'll put up some pictures later tonight, but the wiring goes like this:
Batter-->main fuse-- (solid Reg Rectifer)-->m unit.  In the M unit, there is a wire running out of the AUX, that splits in 2. Wire one splits again, and goes to the R/R switch and some other combo of wires); Wire 2 splits between the power for the Dyna S and the coils.

There is continuity (tested with a light) running to the coils and the ignition. I static tested the timing (it was dynamically tested about a year ago), and the light went out at the F mark for the appropriate coil.

It was getting spark a couple of weeks ago, but nothing recently.

[bryanj]

The circuit for timing is seperate to the circuit for running if i understand the dyna correctly

[Bastaldo]

The RR is a rick's. It has a red wire, a green wire, a black wire, and yellow wires. I believe the black wire is a switch that tells the RR to turn on/off.

I'm now wondering if there is a fuse somewhere in the Dyna S power cord that may have blow. I figured since it did static timing it was fine, but maybe not. But again, the ignition just completes the circuit so i'm not sure why that would kill the spark.

[Bastaldo]

Not sure if the picture does justice but the RR has 2 green, 3 yellow, 1 red and 1 black. The black is connected to the chain coming out of the m unit AUX (which reads 12 v). also coming out of the AUX is the points wire (12 v) and the power for the ignition (12v). The battery is reading 13.05 v.

The rest of the m unit has led head light, rail light, and front and read turn signals, and a horn. The starter is disconnected and there is no SS.

Of note, I just got white and orange spark from the 1,4 and a little backfire with the tank off.

[Bastaldo]

Sorry for the delayed response. Battery is 13.12.  The AUX is 12.04 and the point at which the coils get power (key on) jumps between 11.98 and 12. I switched up the plus and got some better spark but still nothing close to starting up. I also put in new idle and pilot jets and float springs just to make sure everything was clean. And ask no residue in the bowls.