No spark on two plugs 85 Aspy

[tricky]

I am attempting to chase down a problem hoping that someone can help jog the brainwaves a little.... or maybe a lot

The left coil that services plugs 3 & 4 will not produce a spark. The right coil servicing 1 & 2 plugs is fine.
The coil was tested by aircraft electricians who no doubt have better instruments than I, they tested several coils and found all of them that I had to be within spec.
I am troubleshooting with the 85 electrical manual.

Steps 1,2 & 3 page 142 pass muster , there is voltage on the black & white wire on both coils.

step 4 is where it seems to be not quite right.

Connectors 69/68 (black/white wire) coming from engine stop switch is providing voltage

Connector 67 (Yellow/blue) Right coil provides a bright pulsing light when the engine is cranked. (OK) spark at plugs 1 & 2

connector 70 (Blue/yellow) left coil showing a very weak pulsing light when engine is cranked, no spark at plugs 3 & 4 (I have tried swapping coils from my supply)
Just to be sure, I will swap the coils on the bike knowing the right one to be providing spark and see if the results change.

New wires and plugs.
Swapped IGN CTRL unit with another (same result)

Hoping someone can give some insight as to where I can test.

[virgilmobile]

The pulse coils(pulse generators)...
There's 2 of them.. Measure there resistance from the ignition module and again where they plug in from the engine to the harness.
Suspect one is out of specs or corrosion at either plug.
There is a very small voltage on these and any corrosion will weaken the pulse.
Also you didn't mention what the voltage was on the black/white wire.While cranking it should be no more than 1/2 volt lower than the battery.

[tricky]

Sorry for the late response , making use of the summer.

Voltages on the two coils, shut of switch and Ign Ctrl unit (B/W) all read the same,
pretty close to battery voltage.

I think I have uncovered the problem.

I disconnected the 4 pin connector from the PG's On The Y Y/W reading 333 Ohms and the Blue Blue/Wht 330 Ohms Pretty well dead on spec.

When I connected that back I went to the 9 pin got the same reading on the B B/W but on the yellow side ( the offending ) coil it was open (no reading at all)
I disconnected the four pin and checked the continuity on the yellow side it was OK
same with the Blue side.

Some where at the four pin it is not connecting properly although they look clean.

Will get back to it later.

[tricky]

I traced the IGN problem to the 4 pin connector on the PG's It was intermittent. I have it cleaned and now we have IGN.

Thanks for the tips virgilmobile.

Now for the next problem and don't ask me how and why this has started.

Turn on IGN, pull choke on, push the start button, the bike fires up and Idles and if left will eventually reach operating temp.

IF I try to take the choke off the engine quits.
IF I try to turn the throttle the engine quits.

it's got me

[virgilmobile]

You now have a fuel starved engine.
Using the "choke" is actually just a fuel enrichen valve.. effectively bypassing/adding to the slow speed jets.

[virgilmobile]

How long has it been sense it ran ok?

[tricky]

12 months ago I had this one running fine.

I did drain the fuel out of the tank a few weeks ago, added fresh fuel and added some seafoam.

Maybe it will work its way through.

[virgilmobile]

Keep us posted.Keep trying to get to run without the choke.
Run it..choke on then breifly choke off..cycle as needed to keep it running.