Can any of ya'll help with an SR500? Trying to get spark.

scott s

scott s

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I recently picked up a 1980 SR500 that's been off the road since at least '06. Been going through the cosmetics, tune up, suspension, etc.
I can't seem to get spark.

I now have a new coil, new plug, and new CDI and I still don't have spark.

I installed a new battery in my meter and did these tests again: https://drive.google.com/file/d/1ds48JON5ZCEoU92-dm269MFteAf1Pj-t/view



I did the test procedures and originally got high ohm's on the coil (even though low or open is usually a sign), so I installed a new coil. Still no spark. Then I installed a new CDI. Still no spark.

Today, I did the test procedure again. I *think* that everything is OK except maybe test 1C on the ignition switch/kill switch.

Also, I have a cheap meter (new battery for this round of tests) and the sheet says "0.95-1.1R" for the Primary resistance. I'm not sure what the "R" means. I used the 200 OHM scale as that is as low as my meter goes and, since the coil is new, I left the cap on so as not to disturb anything. I got 9.0 ohms on the Primary vs. the "0.95-1.1R" but, like I said, I'm not sure what that R scale means.

Would the 5.0 Ohms on the test 1C be my problem?

I did notice this time that even with no battery installed, I saw the Neutral light come on when kicking it over. I just don't see any spark.

Test page attached. Any help you can offer is much appreciated.

Image_zpsqxhd9xdt.jpg
 
reading an article recently about starting problems with an SR500 and the culprit was a mismatched stator and flywheel.......Food for thought.
 
Did you change the plug wire (high tension lead)?

Potentially annoying questions:
  • is the kill switch on?
  • are the handlebars grounded (does the horn work? - the handlebars must be grounded for many functions to work properly);
  • is there 12 volts on the coil wire?
  • is there paint under the coil mounting screw heads (i.e. is the coil chassis grounded to the frame of the bike)?
Pete
 
Plug wire is integral to the coil, so it's new.

Key switch is on. Kill switch in RUN.

The horn works, but I am getting some funky things from the LH control, like dirty connections for the turn signals, etc. BUT....the RH control only has the kill switch. Refer to test 1C above. The procedure tests the function of the key and kill switches and confirms continuity of wiring TO the CDI box. "Correct" readings are 0-3 ohms. I get 5 ohms on test 1C.

Coil has a special horseshoe ring for proper grounding. It's the "right coil" sold by an SR500 specialist. It wouldn't hurt to check where it mounts to the frame.

The SR500 doesnt need a battery to run. There isn't a way to test for 12V to the coil.
 
650Skull said:
reading an article recently about starting problems with an SR500 and the culprit was a mismatched stator and flywheel.......Food for thought.
Click to expand...

I don't know any history of this bike so I don't know if the stator has been changed, BUT.... I did the test procedure I linked above and get good readings from the stator. I think.

On #5, Low Speed Source, I use the 2K ohm setting on my meter and it shows .334. Is that because I'm reading low ohms on a 2000 ohm scale? The decimal point?
The next lowest setting on my meter is 200 ohms and the nominal readings for test 5 are 325, so I use the 2K ohm scale and get .334 on my meter.
 
Have to physically check to make sure the Stator and flywheel are matched.........In the article, (Aussie Motorcycle trader and the new owner is a regular feature bike owner), the bike was sold because the PO couldn't get it started.....the new owner had help from the Mechanics from the Mag and the SR500 club spending days trying to sort the problem. The stator had been tested as good in the past and was rechecked and tested good.............Then someone made the comment the Stator and flywheel had to be matched. When it was checked it was found they weren't. Got the yamaha part no, found the right part and problem solved..............

Not saying this is your problem Scott, but if you don't know the history, and have replaced the CDI it won't hurt to check.
 
Sorry can't help with that, all it says is matched units in the article.....Parts file from Partzilla against the model/year maybe
 
Yeah, I'm on there. Getting some feedback but, since it's a Yamaha, CDI and a magneto, I figured there might be people here with some knowledge, too.

I found out how to check the stator/flywheel to make sure they're matched (I think). I'll do that tomorrow.
 
I mismatched them on my SR500. The bike would start but not rev up. There was a slight timing change on these in '80 I think. To accomplish that, the pick-up magnet location on the flywheel was moved slightly, probably the pick-up on the stator too. Mine is a '78. I put a later stator on but with the old flywheel. That caused the problem. I put the later flywheel on and all was good again.
 
I'm using a Radio Shack meter. I ohm it out and get 0 or 0.1. This is the reading I get on the primary, so it seems to be good.

primary%20ohms_zpswf0slvzq.jpg


This is test 5 Brown to Black. Should be 330 Ohms. I used the 2K ohm scale and I get .338. Notice the decimal.

brown%20to%20black_zps8zr9ktrw.jpg


This is Test 7, Red to Black. Should be 330 Ohms, I get .330. Again, with the decimal. Is that a function of my meter? Is that 330 Ohms?

red%20to%20black_zpsi8gxw8tu.jpg
 
The "fat" winding on the stator, which I believe to be the Low Speed Pick-up, is at the 9 o'clock position.

9%20oclock%20winding_zpsttthrxaf.jpg


There is another slightly different colored/shaped winding at about 1 o'clock, but it's not as fat as the one at 9 o'clock. All of the rest of the windings are the same shape/size/color; a brown or copper color and much smaller that the one at 9 o'clock.

1%20oclock%20winding_zpske8vlzzr.jpg
 
Hi again Scott.

As I mentioned earlier, I’m not an electrical wizard like some of the other guys on here, but to me, your Tests 5 and 7 results seem to point directly to the problem.. The beauty of digital meters is that they sort out the decimal for you. Your readings are 1/1000th of the correct numbers - and that says either incorrect connection or bad component to me.

If you use the lowest scale (200 ohms, I think) do you still get 0.330 or do you get OL (overload / out of range)? If it’s the former - then you’ve got a bad component I’d say.

....watching with interest.....:popcorn:

Pete

PS: if I had two functional knees, I’d want an SR500 myself!
 
I'm no wizard either, but I was also told that .330 Kohms is 330 ohms. So that would indicate that the test is good.
It was also confirmed that my stator and flywheel match. I'm going to test some of the wiring along the frame going to the CDI and see what I find.
 
Ahhhhhh - yes, it certainly is. I totally missed the "K". dammit - sorry about that.

K means "kilo" which is the Latin term for 1000. So:
  • kilogram is 1000 grams;
  • kilometer is 1000 meters;
  • kilovolts is 1000 volts;
Similarly, "M" means "mega" which is millions and "m" means "mili" which is 1/1000th, etc.

Again - sorry about that.

Pete
 
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?
 

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