Topic: 1980 SR500... In search of spark

[scottly]

Yes, do the test at the same plug as test 1, except between the black and orange wires instead of the black and black/white wires. BTW, the black wire is ground in Yamaha land, and the black/white wire is the "kill" wire; grounded, no spark, open= spark.

[Scott S]

 With the coil connected and the CDI unplugged, I get the same 0.9 across the orange and black.

 Black wire to various places on the frame shoes OL, or open/infinite. However, there are a couple of random spots on the frame, bolts, etc, that I see 0.1 or a very low, shaky reading.

[Scott S]

 This is driving me crazy. I can't find a single thing wrong with the tests. The coil is new, from Rex's. The CDI is new, from Rex's. The plug is new and I tried the old one, too.
 I tried disconnecting the kill switch. I checked the gap on the pick-up; about .030-.032, so that's good. Made sure it wasn't corroded. Pulled the sprocket cover and checked for frayed wires from the stator (even though all my tests are good). Found nothing.
 Verified  that the stator and rotor match....they do.

 What now?

[jgger]

Scott I hope you get this sorted soon. I an personally not too bright on lectric but have you verified the integrity of the ht lead from the coil to plug? You probably have  so I don't want to sound insulting.

The only other thing to do is start checking wires to ground that shouldn't have continuity.

I feel your frustration.

[scottly]

Are the inconsistent readings due to a poor connection on the meter probe? I usually use the center of a screw on an engine side cover to check to frame ground.
The schematic I've been looking at shows three connections to frame ground: the neutral switch (not of concern here), the ignition coil, and the ignition coils under the flywheel. Disconnect the plug with 5 wires from the CDI, and measure from the black wire to a screw on the engine.
Oh, i also saw something that said not to run the engine without a battery, as it could damage charging system parts. Not a problem for testing, I think.

[Scott S]

have you verified the integrity of the ht lead from the coil to plug?
The only other thing to do is start checking wires to ground that shouldn't have continuity.

I feel your frustration.

 The HT lead is integral to the coil. The coil is new and the correct low ohm coil for a CDI ignition.

https://www.epayments.co.uk/epages/es143131.sf/sec6c87bde489/?ObjectPath=/Shops/es143131/Products/HTC10

[Scott S]

Are the inconsistent readings due to a poor connection on the meter probe? I usually use the center of a screw on an engine side cover to check to frame ground.
The schematic I've been looking at shows three connections to frame ground: the neutral switch (not of concern here), the ignition coil, and the ignition coils under the flywheel. Disconnect the plug with 5 wires from the CDI, and measure from the black wire to a screw on the engine.
Oh, i also saw something that said not to run the engine without a battery, as it could damage charging system parts. Not a problem for testing, I think.

 Probably just a poor connection on the probe. One of them, for example, was when touching the painted engine case or a spot on the frame. All of the consistent readings came from bare metal areas.

 Not gonna run the bike without the battery. These tests were done first with no battery installed and the second go 'round with a battery installed. Same results.

[Scott S]

I tested the kill switch.
 I have continuity from the connector in the harness all the way to the CDI plug on both the Black and Black/White wires. I get 0.9-1.0 ohms on those wires.

 I tested the operation of the switch itself and I get:
 OFF 0.4 ohms
 ON  Open, or infinite
 OFF 0.5 ohms

I tested the key switch, going from the Black to the Black/White in the 4 prong plug.
 OFF 0.2 ohms
 ON Open, or infinite.

 I am pretty confident at this point that I do not have a broken wire anywhere in the wiring harness. EVERY test that I do tests good, at least to the best of my ability. I'm stumped and frustrated.

[scottly]

Disconnect the plug with 5 wires from the CDI, and measure from the black wire to a screw on the engine.

[Scott S]

 That would be the one coming FROM the stator? Not the one from the CDI, right?

[Scott S]

Disconnect the plug with 5 wires from the CDI, and measure from the black wire to a screw on the engine.

 Had the GF come help so we could get good contacts and hold the probes steady. On multiple points around the engine, we get 0.2 ohms.

[Scott S]

In my quest for spark, I would like to check the pulse coil.  When I look at the parts diagram, it appears to just screw on. But when I Google images, it shows a short wire lead. I can't see anything on mine.
 How does it attach and is there a way to test it?




 My actual flywheel, pulser and pick-up magnet.

[scottly]

I'm guessing the wire goes through a hole in the stator plate? Is this "pulser coil" one of the two "pickup" coils referred to in the test procedure?

[Scott S]

 I take it this IS the pulser coil, but the SR has a low speed pick up and high speed pickup.  It's what charges/sends signal to the CDI at various RPM's.  Sort of like an advance, Maybe? One of the windings on the stator is huge. That's the low speed pick up. Mine is at 9 o'clock and the flywheel matches. It IS possible to have a mismatched stator and flywheel. Mine supposedly match.

 My next steps are:

 - find out if I can test the pulsed.
 - get a flywheel puller and see if the keyway has slipped.
 - check to see if the rotor has demagnitized.

[scottly]

There are two pickups, one for low speed and one for high speed, and there are two source coils, that act as the power source for the ignition system, the magneto, so to speak. The pickup coils work with the two source coils to provide an advance. The stator also has the AC charging coils, the normal stator coils like on our CBs. The ignition system on the SR, like the FT, is completely independent from the charging system. After research, a sheared key wouldn't prevent a spark on the SR, it would still spark, but at the wrong time. The FT has the pickup, or pulser, mounted on the other end of the crank, so the magnets on the rotor wouldn't be lined up the the source coils at the right time.

[Scott S]

 There's only the one pulser coil that I know of. And since I can't see the wiring on it, I don't know if it's one of the pickup coils tested or not.
 

[scottly]

I'm guessing that coil outside the flywheel is the "low speed" pickup you tested in test#3. Frankly, I'm stumped too. All the meter tests are good..

[Scott S]

 Rick' s Electrics rewinds stators.  I might call them and pick their brain.
 I've been emailing Rex's and they mentioned the CDI again, but I have a brand new one of theirs.

[Scott S]

So, what now?

 Rex's said they've gone as far as they can go via email. I can send the parts in for them to test, but I'm in the US and they're in the UK. The coil and CDI are both new from them, so if the CDI is faulty, it was faulty out of the box.

 I called Rick's Motorsports and talked to them today. They agreed that my numbers are all in spec and if I sent the stator in the readings would likely be the same.
 The did ask if I have checked "trigger polarity". I told them I didn't know what that was and asked how to check it. They directed me here:

https://ricksmotorsportelectrics.com/blog/trigger-polarity-why-is-it-so-important/

 That is the same thing as the pulse coil, no? I can't seem to get any information in the Yamaha pulse coil. It isn't even shown on the wiring diagram. I'm told it's not meant to be removed and I don't have any numbers to test against if I could.
 Plus, I question if that's not what the Low-Speed pickup and High-Speed pickup tests are anyway?

 In serious need of some help here.

[scottly]

Download part 3 of the SR 500 manual from the sticky at the top of the main bikes board. The pulser is mentioned on PDF page 8 (manual page 87), and a schematic of the ignition "stator" coils is on PDF page 9 (manual page 88).

[Scott S]

Download part 3 of the SR 500 manual from the sticky at the top of the main bikes board. The pulser is mentioned on PDF page 8 (manual page 87), and a schematic of the ignition "stator" coils is on PDF page 9 (manual page 88).

 Where are you finding this sticky? On this forum?

 **EDIT: Found them** And that confirms that the tests from Rex's does in fact test the pulser.

[Scott S]

 Mine tests OK. I'm just going to take it up to my buddy's shop after the hurricane passes. I'm calling in the pro's on this one.

[scottly]

Indications are the CDI is faulty, as it is the only part that can't be tested, and all other tests have passed.

[Scott S]

 That's the second part I ordered, right after the coil. I have now tried the stock CDI and a replacement CDI from Rex's. I asked a guy from the SR500 forum if I could borrow a known good CDI unit just for testing.

[Scott S]

 Bumping this up because, guess what? I *STILL* have no spark!

 After testing, testing and more testing, I sent it to my friends shop in Charlotte. He's had it for a few months now (he's mostly European bikes these days, so I was thankful he'd take a look at it) and he can't get spark either.

 His tests on the stator came back bad/low. I may have missed that because I was using a cheap meter and my scales jump from 200 oHm to the kilo-oHm scale.
 He sent the stator to Rick's for a rewind. When it was returned, one of the pick-ups was hitting the flywheel. Sent it back to Rick's and they fixed it. Still no spark.
 My mechanic has traced out the entire harness, just like I did, and found nothing. Tried removing the B/W wire from the CDI (it grounds the spark, killing the engine) and that didn't work, either.

 We confirmed that I ordered the correct CDI from Rex's (I did). We asked Rex's to test both the old and new CDI units but they declined, saying that taxes, import duties and fees make it not feasible.

 -New correct coil from Rex's (includes cap)
 -New plug
 -New CDI
 -Stator rewound
 -Harness and controls checked
 -Confirmed stator/rotor/flywheel match
 -Confirmed rotor has't spun on the crankshaft
 -Checked, tested and cleaned multiple grounds

 Now what?