Help me find spark on my SR500

And we did the test today and the stator is wound correctly. Both pick ups attracted the South end of the compass.
We also checked over a few things that had been checked in the past and simply CAN. NOT. GET. SPARK.

Tried spinning the rear wheel in high gear. Tried giving the coil a second ground to frame. Tried eliminating the ground to the CDI. Tried a different plug cap on the new coil. Tried a different gap on the plug. Tried running power straight to the coil. Checked gap on the low speed pick up. And on and on and on.
EVERY single suggestion that I've been given has been tried. Key switch works. RH control works. Main wiring harness tests good. Flywheel and stator are matched. Flywheel has magnetism.

I, and my mechanic, are truly at a loss. I'm open to any suggestions.
 
scott s said:
Sent these guys an email to see if they can do the SR500 flywheel.

https://www.scooterwest.com/flywheel-re-magnetizing-labor-remag.html

They can't do the SR500 flywheel but gave me a test to try. My mechanic is going to try it and report back. He swears the flywheel feels like it has magnetism. Maybe it's just not enough?
 
Sonreir said:
Did we ever measure the resistance on your ignition coil?

I measured the original coil and, while it was within specs, it was on the low side. The FIRST thing I tried was trimming back the wire to good copper and installing a new cap and plug. When that didn't work, I ordered a new, proper coil from REX's. Today, I tried the new NGK cap on Rex's coil. My mechanic has tried both coils and both CDI units.
 
I'll ask him if he can get those for me. It's up at his shop in Charlotte now and I'm not there.
 
CDI coils will have a naturally low resistance, so accounting for the inherent resistance in the multimeter is an important step. Start off by touching the two leads together on the meter and you should get a low value (around .01 to .05, usually). This value should be subtracted from the reading you get when measuring the coil's primary winding.
 
This is the coil on it now. Supposed to be the proper one for the SR500. Brand spanking new.

https://www.rexs-speedshop.com/product/htc10-sr-xt-tt-400-500-600-ignition-coil/
 
I recall you mentioned that the coil was new, I was just trying to think of other things we could quantify.
 
He's going to check those readings and test the magnets on the fkywheel for me. Probably be in the morning; shop got busy.
 
Rex's HTC10 coil tests: Primary 1 ohm, secondary is 8.8 kOhm without the cap, 13.7 kOhm with the cap.

All of the magnets on the flywheel are strong enough to hold a 19mm wrench against gravity.

Low speed pickup appears to be grounded properly to the unit frame.

The tests continue.
 
1 Ohm should be about the very upper limit you want to see for the coil primary. 0.7Ω would be a bit nicer.
 
Cool. That proves the coil isn't bad (but doesn't prove it's good). Do we know if we're getting a pulse from the CDI box or if we're getting a pulse from the engine pickup?
 
Sonreir said:
Cool. That proves the coil isn't bad (but doesn't prove it's good). Do we know if we're getting a pulse from the CDI box or if we're getting a pulse from the engine pickup?

How do I check that? I replaced the CDI with a new unit from Rex's. After the stator was rewound and still no spark, we tried the old CDI unit again, too. As well as the old coil. Every combination of those things.

To make sure the stator wasn't wound backwards, we used a 6V battery, a test light and a compass. When each pick up was energized, it attracted the South end of the compass pointer from an inch or so away. According to Rex's, that means that the stator is wound correctly.
He said to check that it has "good earth", and it appears that it's grounded to the unit frame perfectly.

I even stuck a test light onto the coil secondary and kicked it over....no light flashy.

How do I test that I'm getting a pulse?
 
Ideally with an oscilloscope, but I'm hoping that a multimeter can verify it as well.

But let's get the easy part out of the way, first. Disconnect the black/white wire from the CDI box, but leave the other wires intact. If the black/white wire is grounded for any reason, it will kill the spark. Removing it from the CDI box will also eliminate any other issues we might be having with the wiring downstream. Also verify that the black wire from the CDI box has a good connection to ground (0.3 Ohms or less is my preferred value).

Try firing the bike up now that we've done those two things. If that doesn't help, proceed with the multimeter testing.

Assuming the colors are the same as stock, we're concerned with the white/green and blue wires coming from the stator and leading to the CDI box. Disconnect the wire or plug from the CDI box and set your multimeter to read AC voltage. Stick the probes between the two wires and then get someone to kick the engine over. You should see some voltage blips on the meter (though I'm not sure about the value).

The pulse from the CDI to the coil is easier. It's about 180V, so disconnect the orange wire from the coil and bridge it to the frame with the multimeter set to read DC voltage. If your meter has a peak-and-hold function, this would be useful. With the CDI reconnected and the ignition switch turned on, kick it a few times and see if you're getting at least 100V to the ignition coil.
 
Already tried the Bl/W wire trick. Both at the rear by the plug and by completely bypassing the RH switch and the ignition switch. No Go.

I'll forward the CDI instructions to him.
 
BTW, I really appreciate you chiming in on this. It's been a real ball buster. I'm just an amateur but, usually, I can stick with it, think it through, ask questions and follow directions and figure it out, be it mechanical or electrical.
This one completely stumped me and my Dad. Took it to my buddy who runs a thriving shop and is no slouch, and he doesn't get it either.

EVERYTHING tests good. Per the manual, per Rex's troubleshooting, per hints and suggestions we've gotten. EVERYTHING is in spec.
The switch and controls are tested at the rear of the bike, which means you're testing the main loom at the same time. All the tests are good. But THEN...we tested each component separately; ignition switch and RH control up at the headlight, then the loom from headlight back to rear of bike. All good.
Rigged up extra grounds. Tried UNgrounding the CDI. At one point, he had a temporary loom set up that completely bypassed the key and RH switch. Nothing. Power straight to coil. Nothing.
Over and over and over.....
 
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