Well I did order a new ICU when I ordered the coil a couple weeks ago. I'll try to check that tonight.

I had a similar failure a couple of weeks ago. At first i thought the coils were at fault, as there was a huge crack. So i changed that. Still no spark. Then i did some multimeter testing and guessed that the ICU was faulty. Changed that to the latest version, and got a spark. The bike started but ran rough. It wouldn't restart once warm. I remembered reading somewhere that a bad voltage regulator could cause that, so i changed it (from the high output version back to the standard). It then started and runs perfectly.

The coils that cracked and the regulator were only a couple of years old.

And then last week a friend's R80 G/S did exactly the same. He traced the fault to the ICU, fitted my old ICU (the one that i thought had broken) and now it run perfectly again.

Airhead electrics are a dark art. My friend is an engineering professor, but even so, still found it all quite mysterious.

Yet another cracked Bosch ignition coil.

https://pbs.twimg.com/media/BoRL2WJCcAE_Uy7.jpg

Mine has spark (and even more spark now with the new upgraded ICU that shocked me while holding the plug by the cap as I found out a couple days ago) but still won't run. I'm going to check the compression this weekend and if that's good then I guess it's a timing issue.

Would be interested to know if you've solved the problem.

No, I'm going to check the compression soon. I have a tester, I just have to read up on how to do it. I guess just ground the plug to the cylinder, open the throttle and crank it.

That should do it. If it's low squirt a little oil into the cylinder and re-run. If it improves it implies rings rather than valves.

Did the compression check last night and I got 75 psi on the right cylinder and 80 on the left. I popped a carb off and squirted a little starter fluid in the manifold and it wouldn't even fire. I have replaced the coil & ICU and I can see the plug sparking so I'm thinking it has to be out of time, right? I'll look into checking this.

Anybody have a spare bean can laying around that I can borrow?

The timing has to be very wrong if it's not able to ignite starter-fluid! On the first page in this thread I've described how to check timing with a volt-meter.

It's harder to ignite under compression. I would have tried starter-liquid with the carbs still on the bike and with the throttle closed.
Worn plug-cables will give the same symptoms, you should also check the ground-wire for the ECU (separate wire that goes to the left bolt for the upper engine-cover). Have you changed the plugs?

I've also tried squirting starter fluid into the airbox a few times with no luck. That's why I tried with the carb off.

Both plug cables are registering 5kOhms and I have changed the plugs. I'll check the ECU ground wire and timing soon.

Based on the instructions in the Clymer for testing the electrical components I think that I could possibly have a bad connection between the ignition switch (key) and the on/off selector but I'd like to test that before going through the wiring harness. It has an aftermarket enduro computer on it with the key attached so I'm not sure where it's wired in. Could I run a jumper from the battery to the green wire on the coil to gaurantee that a good 12V is supplied?

For test purposes: Yes

When you try to connect the green wire directly to the battery it will also power up the ICU (and more). Some ICU's turn off after a while (30sec?) when the engine is not running. So you have to connect the wire directly before you attempt to start.
When doing this remember that you might have to remove the wire to stop the engine.

Should I remove the green wire and hook the jumper up to the coil's spade or just attach it to the connector? Can I use a thin wire or will the power going through require a thicker wire? My jumpers are really thin.

If you leave the green wire in place you will also power up the ICU which might be a good thing. If it starts with the green wire in place you can try to remove it to see if it still starts.

Most wires will work. If the wire is to thin it will be hot, but then you can use 2 or 3 in parallel.