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Author Topic: Help me find spark on my SR500  (Read 276 times)

Offline scott s

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Help me find spark on my SR500
« on: Sep 10, 2018, 08:58:55 »
 I recently picked up a 1980 SR500 that's been off the road for years:  http://www.dotheton.com/forum/index.php?topic=75801.0

 I can't get spark for the life of me. I did the test procedures from Rex's Speed shop.

https://drive.google.com/file/d/1ds48JON5ZCEoU92-dm269MFteAf1Pj-t/view

 Initially, the only thing that came back wonky was a very HIGH reading on the coil secondary. Usually low or open is bad. Either way, ordered a new coil from Rex's. This is the proper 1 ohm coil with proper grounding for CDI, etc.

http://www.rexs-speedshop.com/epages/es143131.sf/en_US/?ObjectPath=/Shops/es143131/Products/HTC10

 Installed that and still no spark. The test procedure tests the wiring going TO the CDI, but there's no way to really test the CDI. So, I ordered a new CDI from Rex's. Still no spark.
 I've gone through the test procedure twice more. I've done it with and without a battery in the bike (the SR500 will run without the battery. The battery has nothing to do with the ignition). I can't find anything wrong.
 One slight oddity, and I don't think it's an issue, is that my Radio Shack meter reads on a 200 ohm scale, then goes to a 2K ohm scale. Some of the stator windings are supposed to be 330 ohms. I use the 2K ohm scale and get readings with a decimal in front. BUT....isn't .330Kohms the same as 330 ohms?
 Rex's is telling me to sort out the issue with the meter, but if I understand it correctly, those readings are good.



 -I checked that the stator and flywheel are matched. They are.
 -Tried a new plug and the old plug.
 -Pulled the sprocket cover and checked for frayed wires from the stator (even though tests are good). Found nothing.
 - Checked from the coil to the CDI and get the same 0.9 ohms (good).
 - Tried unplugging the kill switch. No spark.
 -Checked the gap on the pickup and got .030-.032, so good.

 And on and on and on. What next? Why don't I have spark?
 

Offline scott s

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Re: Help me find spark on my SR500
« Reply #1 on: Sep 10, 2018, 13:39:20 »
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.

Offline Hoofhearted

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Re: Help me find spark on my SR500
« Reply #2 on: Sep 22, 2018, 03:03:41 »
I never had an SR.  I did have an SRX which had a habit of losing the spark,  I don't know if your SR came with a sidestand "kill" switch.  The SRX had one.  If you do have a sidesatand switch take a look.
El Mirage record 500 APS/PG 129.817
El Mirage record 500 SC/PG   122.240
El Mirage record 500 SC/PF    120.157
Bonneville record 500 SC/PG  119.667
Bonneville record 500 SC/PF   117.186
Bonneville record 500 SC/PBG  111.494
Bonneville record 500 SC/PBF   112. 600
Bonneville record 650 SC/PF   128.703
El Mirage  record  650 SC/PG   130.224

Offline scott s

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Re: Help me find spark on my SR500
« Reply #3 on: Sep 22, 2018, 07:46:25 »
 No sidestand switch.