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Thread: No Spark On My 500F Roadster

  1. #1
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    No Spark On My 500F Roadster

    Background:
    1. Normally a 1 kick starter cold w/choke & 1 and 2 kick starter when hot.
    2. NOS R. HB switch when I did the build.
    3. I rarely (can't remember when) use the kill switch. I usually shut down with the keyed ignition (OEM).
    4. I'm electronically challenged. I can route wires, make good connections, but that's about it.

    Problem:
    Occasional idle difficulty (nothing serious) that I thought was loose particles blocking the idle jet from time to time. On 2 occasions it failed to start after a rough idle killed the engine @ a stop light. After a lot of kicking, swearing & resting & about 15 minutes of doing nothing, it cranked.

    I made a mental note to clean the carb but got back involved in my GB500 build. Two days ago I disassembled the carb & did not find any foreign particles: It was as clean as a new one. I blew out all openings & reassembled. I reinstalled with new fuel line & a new filter.

    Today I attempted to crank & no success. I pulled the spark plug, grounded it against the cylinder head & no spark. I even tried it inside the shop with no lights & not the tiniest spark.

    I pulled the tank & checked all connections & everything looks OK. I even turned the kill switch back & forth & no spark.

    I need some suggestions & in the order of the simplest to perform. I have a running 500E future project bike that I can rob parts from, but I know that the electrical components are not always the same even though they look the same.

    I have a multi-meter, but am not very knowledgeable on all of the functions. I was thinking about checking the kill switch 1st., but am open to any suggestions.

    Thanks,
    Henry

  2. #2
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    May as well check the stator first thing.
    Find the plug connector that goes to(and near) the regulator and unplug.
    Test the wires coming from the stator on this plug.
    Set your multi meter to the lowest OHMs scale, usually 200
    To test the charge coil.. positive lead on the multi meter to the white wire terminal and the negative to the yellow wire should read .73 ohms or close
    next check the white to white wire ..should be .8 ohms or close
    to check the source coil(the one that usually fails..) change the meter to the next highest ohms scale.. usually 2000
    check brown to black wire...should be 329 or close then
    check red to black wire...should be 334 or close
    it is very rare the pick up coil is bad
    to check the ignition coil
    meter at 200 ohm scale
    between the positive and negative wire on the coil .98 OHM or close
    move the dial on the meter to the 20000 range, from the positive terminal on the coil to the end of the spark plug lead(cap removed) 12000 ohms
    Before you start set your meter to the lowest OHMS range and touch the two leads together, the number you see on the meter will be the resistance in the leads. Always subtract this number from the reading you get checking the wire terminals.
    If you get readings similar to the ones listed, then you just saved yourself a ton of money.
    Since the SR ignition system is separate from the lighting system, you can ignore things like fuses, battery ..
    The problem will be then probably be a wiring break/short, ignition switch or kill switch failure.
    Sometimes it pays to recheck anything that was done on the bike since it was last running,,,, maybe the headlight bucket was removed and a wire came unplugged ???
    good luck

  3. #3
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    Quote Originally Posted by bmonk View Post
    May as well check the stator first thing.
    Find the plug connector that goes to(and near) the regulator and unplug.
    Test the wires coming from the stator on this plug.
    Set your multi meter to the lowest OHMs scale, usually 200
    To test the charge coil.. positive lead on the multi meter to the white wire terminal and the negative to the yellow wire should read .73 ohms or close
    next check the white to white wire ..should be .8 ohms or close
    to check the source coil(the one that usually fails..) change the meter to the next highest ohms scale.. usually 2000
    check brown to black wire...should be 329 or close then
    check red to black wire...should be 334 or close
    it is very rare the pick up coil is bad
    to check the ignition coil
    meter at 200 ohm scale
    between the positive and negative wire on the coil .98 OHM or close
    move the dial on the meter to the 20000 range, from the positive terminal on the coil to the end of the spark plug lead(cap removed) 12000 ohms
    Before you start set your meter to the lowest OHMS range and touch the two leads together, the number you see on the meter will be the resistance in the leads. Always subtract this number from the reading you get checking the wire terminals.
    If you get readings similar to the ones listed, then you just saved yourself a ton of money.
    Since the SR ignition system is separate from the lighting system, you can ignore things like fuses, battery ..
    The problem will be then probably be a wiring break/short, ignition switch or kill switch failure.
    Sometimes it pays to recheck anything that was done on the bike since it was last running,,,, maybe the headlight bucket was removed and a wire came unplugged ???
    good luck
    Thanks so much for your detailed explanation of how I am to go about checking the stator.

    The only thing done since it was last running (though not perfectly....as I explained) was the carb cleaning.

    Henry

  4. #4
    Have you tried replacing the spark plug with a new one? Maybe you will get lucky and find it is just a bad plug.

  5. #5
    Senior Member gcrank1's Avatar
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    The ignition fires off the stator when the engine spins, via the CDI box&coil, is always 'live' when the engine spins (assuming all is good). The Key and Kill switches do not route + power to the coil like traditional battery/points ignition bikes. Those switches GROUND out the CDI to stop it running.
    I had not dissimilar issue, my first check was to disconnect the Kill Switch from within the headlamp shell (to 'get it out of the loop', no diff though), then unplug the CDI box connector and discovered the kill wire was continuity to ground. Back-checking the wire got me to the Key Switch. I found at the bottom of the switch, where the wires feed into it had worn through one wire sheath only, the 'ig. grounding wire' that is only supposed to be shunted to grd when the key is turned off, was grounded all the time.
    It took me and my multimeter all of about 15min. to find the problem. NO hot + power is needed to check this grounding loop. Removing and refurbing/dielectric greasing (they are serviceable) the key switch took some pleasant time on the bench. It may be good for decades again now.
    BTW, after doing continuity checking with the meter dont forget to switch it to 12vdc IF you want to check a Hot circuit! It will blow the fuse and render your meter......ummm,inoperative (dont ask......).
    Last edited by gcrank1; 10-02-2017 at 05:43 PM.
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  6. #6
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    Quote Originally Posted by teledan View Post
    Have you tried replacing the spark plug with a new one? Maybe you will get lucky and find it is just a bad plug.
    That was the 1st. thing I did, but the plot of this story seems to be more complicated.

  7. #7
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    The multi-meter & me: day 1

    Following the excellent instructions by Bmonk here are the results comparing 2 different multi-meters (my wife says I'm OCD)..........all numbers are net after deducting the lead resistance.

    Stator charge coil: W+ to Y-=0.8 on MM#A and 0.7 on MM#B. : W to W=0.8 on MM#A & 0.8 on MM#B

    Source coil: Brown to Blk.=330 on MM#A and 325 on MM#B : Red to Blk.=335 on MM#A & 354 on MM#B (?)

    Coil: Between + & - lead=1.0 on MM#A and 1.1 on MM#B : +lead to plug lead=10.56 on MM#A & 10.22 on MM#B

    I was sure to check the + lead to plug lead on the 20K setting. I even reread the instructions & at this point thought I had determined that the coil is the culprit. I checked www.partzilla.com & determined that a new coil is available from Yamaha (list is $185.62 & Partzilla's price is $123.39).

    I then checked the part # for the coil on the 500E & they are the same. I have a 500E that is a future project bike that was running before I did some partial disassembly (probably 2 or 3 years ago). I did a coil check on it with the following results on the + lead to the plug lead with MM#B (the newest) & it is 10.46.

    Apparently I'm not doing the + lead to plug lead correctly. Is the 20K MM setting correct?

    Bmonk, I'd appreciate you input again.

    Gcrank1, thanks for your suggestions After I get the stator/coil check behind me, I'll move on to the areas that you point out (I'll save the H/L "opening" for last....not my favorite area to work on).

    Henry
    Last edited by oldhenry; 10-02-2017 at 09:48 PM.

  8. #8
    Just like gcrank1 I found the kill switch and key switch both kill the ignition (the key switch is two separate switches one on top of the other, one for the ignition circuit and other for the lighting circuit)
    On my bike the key switch was faulty and killed the spark, so I by-passed it and just use the kill switch now.
    To check,pull the plug to disconnect the key switch and run a meter on the two terminals, one way should be open circuit and the other zero resistance (or very close to it.)

    davy
    Last edited by Old Cafe Racer; 10-03-2017 at 04:41 AM.
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  9. #9
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    oldhenry,
    From the numbers you have posted ,I think that your stator and coil are OK.
    May as well check your pick-up coil, that's the small winding that acts like a set of contact breakers..
    white/red wire to black should be 16 ohms
    white/green wire to black should be 87 ohms

    What we are looking for (in all these tests) is a reading that shows a broken or burnt wire in the coil we are testing.
    When this occurs you will get no reading at all on your meter. A reading of a component out of spec is telling you that the part is coming to the end of its useful service life.
    In your case you have NO spark at all so if your pick up coil gives a reading then you have a broken wire or bad connection somewhere..

    the multi meter range you choose must be greater than the spec of the part you are testing.
    The closer you can come to the maximum of the part on your multi meter the more accurate your reading will be.
    So if you are getting a 1. and a 10.56 on your ign coil that is inside the plus-minus 20% or pretty close and unless you have a very expensive meter there is always a certain amount of meter error anyway.
    I just use cheap meters and I have found that when the results between the two(yes I also use two) meters vary it just telling me that one of them is soon to need a new battery.
    Last edited by bmonk; 10-03-2017 at 06:58 AM.

  10. #10
    Senior Member MadMax's Avatar
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    An article from Marcus @ Speedshop https://drive.google.com/file/d/0B0B...xmS2l3YW8/view

    He maintains that ignition problems can and will be evident at <10% tolerance of stated value, he's the electrical guru.........

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