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

Offline scott s

  • *
  • Posts: 1391
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:

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

 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.

 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

  • *
  • Posts: 1391
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

  • *
  • Posts: 2076
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

  • *
  • Posts: 1391
Re: Help me find spark on my SR500
« Reply #3 on: Sep 22, 2018, 07:46:25 »
 No sidestand switch.