Help me find spark on my SR500

Are you using a stock CDI box or one from Rex's?

scott s said:
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.

This might be academic, but the coil shouldn't have power. If the coil has two wires, one should go to the CDI box and the other should be grounded.
 
Using Rex's CDI.
When I tried new coil/old CDI and didn't get spark, I got Rex's CDI.
When I still had no spark, I had Rick's rewind the stator.

When we STILL had no spark, we tried every possible combination of old/new coil and CDI.
 
And I probably misstated that about the coil. I believe what he did was bypass the harness and went straight to ground and coil.
 
Rex's keeps going back to the stator, specifically the low speed winding. That gives me some pause, because that's the one that Rick's rewound a little fat on the first go round. It was touching the flywheel. We sent it back and he repaired it, but....

Per Marcus at Rex's: "There’s a ring terminal thats integral to the winding that the mounting bolt goes through, check here.

Another thing I’ve seen - the ‘ear’ that the low speed pick up mounts to breaks off. We’ve seen several bonded and even one welded repair that was so poor there was no earth to the rest of the stator! Check the stator hasn’t been repaired here."

He also said the coil tests are good.
 
Some random, thinking out loud questions, for when we do the next round of tests.

- If spark is killed by grounding the CDI (yes, we tried the trick of removing the ground wire), if the main harness has some unseen ground....say, along the frame or in the headlight bucket....would that kill the spark?

- If so, would the harness test good for continuity (it does)? Also, the tests that Rex's has for the ignition switch and RH control/kill switch are done at the rear of the bike, back where the stator and CDI plug in. That takes into account the wiring harness. But we've tested each component separately too. Would an unseen ground that kills the CDI have shown up during those tests?
 
You have done basically everything.....you should have spark:) Unless you burning out electronics when its connected then your down to the wiring harness...If it was me Id rewire the whole ignition circuit bypassing switch's and the main harness, connect directly to a battery...then if no spark test each component.....it has to be something simple, it normally is when its such a butt kicker....
 
wozza said:
You have done basically everything.....you should have spark:)

No shit. That's what makes this such a ball buster.

I'm going to try the pulse test that Sonreir suggested if my mechanic doesn't get around to it first. I plan on going back up there in a week or so and I'll check the harness and wiring myself, but this was a one owner, unmolested bike and I don't remember seeing any damage anywhere.

If we don't find anything, I'm probably going to pull the coil, CDI and stator and ship it all to Rex's so they can test it all out.
I've found a new main harness for $70 and may try that. The ignition switch and RH control have been tested to death, but I'll look around in the headlight bucket, too.

Another sanity check question: the handlebar controls had a locating "wedge" or tab. Honda uses that round pin; Yamaha had a straight tab that fit into a slot on the stock handlebar. I swapped bars and bent that tab down so the controls would fit the new bars.
Would that cause an issue? Should they touch the bars? Or NOT be touching? Or ??
There are thousands of SR's out there with swapped bars, so I don't think it's an issue. BUT.....sometimes it's the stupid stuff.
 
Tested the stator today. With the meter set to AC and hooked up to the White/Green wire and Black wire, we're getting 36V to over 100V AC. So that means the stator is good, right? Or, could the low speed pickup still be bad and we're reading off the other pickup?

Tried to test the signal coming out of the CDI to the coil and get basically nothing. Mili-amps at best. That points to a bad CDI, right?
 
Also, when I got home with the bike in the truck, the stator was at eye level. That's when I noticed that the ears or tabs on the low speed coil looked a little funny to me. One of them isn't flat or horizontal. And the gap is about .008". I had the specs for the gap somewhere and can't find them now.
Does this look funny to you? Would this cause a problem?
 

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I don't know what that pickup is supposed to look like, but that's unusual like that. Small gap is usually OK but with that odd angle., maybe it is not sending a clear trigger to the CDI. Is that a new pickup and if not try to get a new one. CDI output should probably be 300-400 volts.
 
That is a rewound stator, which includes that pickup. Rick's did it and, initially, that winding was too fat and was hitting the flywheel pickup. Sent it back and they rewound it.
Now I'm skeptical about it. Rex's swears there's still a problem with the low speed coil (that one).

We're getting nothing out of the CDI when we plug everything back in and did this:

"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."
 
180 is lower than I expected, but fine if that's what yours generates... That isn't the low speed coil though. That's the pickup or trigger. On the stator there should be at least two coils. One is low speed - typically a fat coil and a high speed - typically thinner. Plus a bunch of lighting/charge coils.

How did the stator wires check out compared to spec? I wonder if it's possible to get an aftermarket pickup to replace that one. Typically they are a separate part but I do remember some OEM setups where it's on the stator.

If it's practical to send the whole set up to Rex, that would be a smart move. I have a test bed that I use for Hitachi and other two stroke twin set ups to check for spark and if the low speed charge coil is bad, the unit won't spark until over 1000 revs and if it's good it should fire at less than half that speed. Rex knows what the specs are for that unit and should be able to test it for you I hope.

In that video, what was the multimeter connected to ? Voltage looked low even for low revs. What did it generate?

Did this bike run with those parts on it before? or was it DOA? looks like a parts mismatch is common on those bikes. It's possible it has the wrong model rotor for that stator.
 
I pulled the stator today and was able to get some better pics.
I contacted my mechanic about what I found. He's willing to send it back to Rick's. I sorta feel like I paid for a service from Rick's (ran through the shop) and he ought to make it right.
But he's had two shots at it and it's not right. That low speed trigger doesn't even look like it was rewound using my original parts. The ears/tabs/triggers....whatever they're called... don't look like the original parts.

So, what to do? Send it to Rex's in England and wait? See if Custom Rewind in Alabama can fix it? Make Rick's make it right?
 

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The gap is critical. Mine is not only incorrect, it's not centered over the pickup magnet.
 

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garys guys at custom rewind have been helping the cx500 crowd for a long time he does excellent work
 
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