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  1. #1

    Join Date
    Nov 2010
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    Austin, Texas
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    49

    No Spark and Timing Problems

    I have run into a big wall on the restore of my '72 CB175. Was wondering if someone could point me down a path(s) to getting some resolution. There's a lot of issues with it, but for now I'll focus on the main problem, no spark.

    I finally got it running the other day. Was letting it sit and idle for a bit to run some Sea Foam through the engine. After about 15 minutes of idling steadily, it died suddenly. No sputter, no slow down then die. Just a sudden stop.

    Pulled each plug out to check for a spark, neither plug has a spark.

    At this point I thought I would check the breaker points. I adjusted the gap slightly, put some contact cleaner on the points, scrubbed them a bit with a point file. While I had the cover off, figured I would look at the static timing. Using a simple volt tester (like this http://cl.ly/3azi) I clipped the alligator clip to the breaker point (where the wire connects to it) and then touched the other end to the engine block. From what I understand, the light on the tester is supposed to light up right when the "F" mark on the rotor hits the index mark. But, my light stays on no matter where the rotor is turned. Never turns off no matter where the rotor is turned.

    What's going on here? And, am I doing something wrong with the timing light?

    Edit: typos
    Complete and total amateur
    1972 CB175 K6 (restore project)

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  3. #2
    Sensei 66Sprint's Avatar
    Join Date
    Sep 2008
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    Stephen Lohmeyer,3839 Sun Valley Lane, Roanoke, Virginia 24014 540-525-5199Sixtysixsprint@aol.com
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    18,387

    Re: No Spark and Timing Problems

    #1...Adjusting the gap changes the timing.....
    #2... If the light does not go out, the points aren't closing, so of course there will be no spark ...Spark ONLY occurs as they break open....
    #3.....The 175 coil HAS to have both plugs grounded in order to work, This pic may explain.....


    The current in the 175 type coil is (like) a transformer... The secondary has NO physical connection to the power source....It has to jump to ground through both plugs to complete the circuit "loop"... It is not the same as a "power fed to one end" coil (like a 350 or 450, which has a common positive feed to both primary and secondary windings) and completes the circuit through the battery.....


    Edit note:...I figure there are enough 175/200 owners to make this a "sticky" for awhile..... Steve

  4. #3

    Join Date
    Nov 2010
    Location
    Austin, Texas
    Posts
    49

    Re: No Spark and Timing Problems

    Steve, thanks a ton for the info. Point #3 is especially good to know. I always leave one plug installed, pull the other out and hold it against the head while kicking the bike over to check spark.

    And, it sounds like I first need to check the contact breaker to make sure I didn't mess up the contacts when I cleaned them. Then go from there. Timing and all.

    Thanks again.
    Complete and total amateur
    1972 CB175 K6 (restore project)

  5. #4
    Sensei 66Sprint's Avatar
    Join Date
    Sep 2008
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    Stephen Lohmeyer,3839 Sun Valley Lane, Roanoke, Virginia 24014 540-525-5199Sixtysixsprint@aol.com
    Posts
    18,387

    Re: No Spark and Timing Problems

    Just FYI, IF even one plug fouled from idleing, neither will fire because of the coil wiring.... AND.....They won't run with a dead or weak battery

  6. #5
    Super Moderator
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    Apr 2010
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    Annapolis, MD
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    4,640

    Re: No Spark and Timing Problems

    I love SeaFoam but if you give it too much too fast it will fowel the plugs. and seems likely to be the cause of your initial stalling and no spark condition...get the points back into shape and clean or replace the plugs and you should be fine.
    CB350 K5 - Uber Café- Engine build 3
    CL350 K4 - Cafe build done waiting on final assembly
    CB350 K0 - Full restoration w/Hondaline bags & fairing
    SL350 K2 - Bubba Shobert flat track build on deck
    CB-1 400F - unrestored mint rider
    2012 Guzzi V7 Racer - Daily Ride

  7. #6

    Join Date
    Nov 2010
    Location
    Austin, Texas
    Posts
    49

    Re: No Spark and Timing Problems

    Again, this is all great info. One plug is very black, the other looks almost perfect. I did dump quite a bit of seafoam into my gas tank. So, that one plug fouling looks to be the likely start of my problems. Started bike, basked in the glow of my achievement, dumped a bunch of Seafoam in the tank, bike dies 15 minutes later, I likely screwed up the contacts when cleaning/adjusting.

    Also, FYI, battery is good, only a couple of weeks old, recently charged and checked.

    I'll report back this weekend after I've gone through all this.

    Thanks again.
    Complete and total amateur
    1972 CB175 K6 (restore project)

  8. #7
    Super Moderator
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    Apr 2010
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    Annapolis, MD
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    Re: No Spark and Timing Problems

    keep in mind that if your tank is still full of seafoam you're likely to fowel the plugs again...did you measure the ratio of seafoam you added to the gas? SeaFoam offers differing ratio suggestions depending on what you want to achieve. they have a low ratio intended as a permanent gas additive for running all the time. they also have much higer ratios for fogging the engine for long term storage which is intended to stall the motor like it sounds like you did.

    when you "unpickle" the motor from this fogging condition they usually smoke like hell for 10 minutes or so and need to at least clean the plugs again after it clears up.
    CB350 K5 - Uber Café- Engine build 3
    CL350 K4 - Cafe build done waiting on final assembly
    CB350 K0 - Full restoration w/Hondaline bags & fairing
    SL350 K2 - Bubba Shobert flat track build on deck
    CB-1 400F - unrestored mint rider
    2012 Guzzi V7 Racer - Daily Ride

  9. #8

    Join Date
    Nov 2010
    Location
    Austin, Texas
    Posts
    49

    Re: No Spark and Timing Problems

    Outobie, again, thanks for the info. In particular, about the smoke. The bike had never smoked one bit, until I did the Seafoam treatment. So that explains that.

    Yes, I put in the recommended amount of Seafoam into the tank. My plan is to clean/replace the fouled plug, let it run a bit longer on the fuel that is currently in the tank that is treated with Seafoam. Then, drain the tank, replace the fuel with some fresh fuel, clean the plugs again and hope it is good to go.

    Thanks again for answering my smoke question, before I even asked it.
    Complete and total amateur
    1972 CB175 K6 (restore project)

  10. #9
    Super Moderator
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    Apr 2010
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    Annapolis, MD
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    Re: No Spark and Timing Problems

    I used to have a summer job in a marina that fogged all the boat engines for the winter with seafoam.

    Every spring the whole marina would look like some creapy movie for about 3 weeks as all the boats were put back into service for the summer with all the heavy fog rolling out of the "unpickled" engines.

    once it's all run through the system ( assuming everything is adjusted properly) your bike should run better sine the seafoam does a good job cleaning out the carb jets, intakes, valves and combustion area. I've always been pleased with the results.
    CB350 K5 - Uber Café- Engine build 3
    CL350 K4 - Cafe build done waiting on final assembly
    CB350 K0 - Full restoration w/Hondaline bags & fairing
    SL350 K2 - Bubba Shobert flat track build on deck
    CB-1 400F - unrestored mint rider
    2012 Guzzi V7 Racer - Daily Ride

  11. #10

    Join Date
    Nov 2010
    Location
    Austin, Texas
    Posts
    49

    Re: No Spark and Timing Problems

    Thank you all again. I replaced my fouled spark plug. Then pull the contact breaker out, cleaned it, and filed the contacts. Once it was all put together, adjusting the timing was a relatively simple task. After that, it started on the second kick and ran pretty well.

    Yeah, it still smoked for a bit due to the Seafoam. But, that dissipated after a bit.

    Now, on to the next problem, high idle speed. I'll mess around with that for a bit and post in proper sub-forum if I once again run up against a wall.

    Thanks again. You guys are geniuses.
    Complete and total amateur
    1972 CB175 K6 (restore project)

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