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Read My Plugs

Discussion in 'The Garage' started by DirtyErnie, Jul 8, 2018.

  1. DirtyErnie

    DirtyErnie Renaissance Hick

    After missing the last two summers, I finally got the bike rolling today. I've changed to Ninja 500 carbs and a stock 2-2 exhaust.
    What do you see in my plugs?
    I see:
    1. The vacuum leak at idle, inner throttle shaft seals are out.
    2. Too much timing.
    3. Wrong heat range? These are the stock spec plugs, and I put a good 20 miles on these with a few hard pulls. Expected to see more color on the threads, but???
    4. Looking down the nose inside the plug, the base of the insulator has a white ring around it, and then the nose is black all the way to the tip. Go up 1 on the main jet and drop the needle a bit?, Pull the stator and shuffle the mag pickups a bit?

    Bike wasn't exactly smooth or powerful in top gear (15+ mph headwind, 17/34 sprocket w/OD 5th), it felt lame rolling into the throttle with a little pulse towards full throttle, and then just a blaaaaaaaaaah.....


    Felt great to be on a bike again.
    Thanks!
     

    Attached Files:

    MaxPete likes this.
  2. angus67

    angus67 Welder's penetrate deeper!!

    Looks lean, but if your using ethanol gas, it takes 50+ miles to get color. Ethanol free gas will show a lot sooner. Is one plug wet? Is it gas?
     
  3. 5twins

    5twins XS650 Guru Top Contributor

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    Today's clean burning fuels don't color up plugs as readily as the gas from years ago did. Your plugs don't look too bad to me but we can't see down in them to "read" the insulator. That's where real "fine tuning" plug reading takes place. You want a ring of color down at the bottom of the porcelain, the upper part clean. If you start the bike using the choke, that will blacken the whole plug in a jiffy and can throw your plug reading attempt off. It takes a good ride to burn them clean again but you appear to have done that.

    Once your jetting is close, plug readings aren't going to change much from minor jet changes or adjustments. You'll have to rely more on "feel", how the bike is running and reacting to throttle (stumbles, flat spots, etc.).

    I see you're running resistor plugs. Is there some reason for that? Normally we don't use them because there's already resistance in the plug caps.
     
  4. DirtyErnie

    DirtyErnie Renaissance Hick

    Yeah, because I'm not running resistor caps. I'm running the black 'KungFu' coil and some MSD racing plug wires with 45° caps and usually Iridium plugs. Ignition is set up like a modern automotive waste-spark system.
     
  5. DirtyErnie

    DirtyErnie Renaissance Hick

    This is ethanol-free, 91 octane from the local Super America station. As I said, inside the plug, the base of the nose has a white ring, then it's black to almost the tip of the plug nose.
     
  6. DirtyErnie

    DirtyErnie Renaissance Hick

    Ok, this might be a thing. After I got home from the ride today, I shut the bike off in the street and then scoped out the leaking throttle shaft seals with some carb cleaner and an idling motorcycle. Definitely pig-rich'd both cylinders with that. Sounds like another ride is in order.

    Damn, I hate it when that happens...
     
  7. xjwmx

    xjwmx XS650 Guru Top Contributor

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    You ought to fix the throttle shaft seals before you do anything else.
     
  8. DirtyErnie

    DirtyErnie Renaissance Hick

    That's definitely going to happen. Leaky throttle shafts shouldn't mess with the WFO main jet, though. There's not a lot of vacuum to be leaked into in that regime.
    The problem is, I don't see throttle shaft seals on the parts list/microfiche. This could get ugly.
     
    Last edited: Jul 9, 2018
  9. 5twins

    5twins XS650 Guru Top Contributor

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    DirtyErnie likes this.
  10. DirtyErnie

    DirtyErnie Renaissance Hick

    5Twins for the win!

    I've been here for a while, that link linked to the thread I started (but never finished?) on the BS series throttle seals. hehehe
     
    TwoManyXS1Bs likes this.
  11. DirtyErnie

    DirtyErnie Renaissance Hick

    No joy on shaft seals. Just can't find anything, and there's just a thin nylon washer between the carb body and the Jeebus clip.

    Lowered the needles a notch. Top gear roll-in cleaned up. Still a little fat about 4,500... Just before the main jet takes over. Plug nose cleaned up farther (lean from vacuum leak), but still black farther down the nose.

    Still too much timing.

    I have MicroSquirt on my mind...
     

    Attached Files:

    Paul Sutton likes this.
  12. DirtyErnie

    DirtyErnie Renaissance Hick

    Lowered the JJJ needles to their lowest setting. Plugs cleared up and are no longer black. There's still some ugly burble as you crack open the throttle at speed, so lowering the needles didn't help that. Going to change the Straight-30 oil for 20w-50 in the morning and go to work. Mileage last trip: 36.5 (was slightly less before). Seriously considering moving the crank sensor pickups.
    Must be hot, the Yamabond got real dark.

    20180814_224455.jpg 20180814_224822.jpg 20180814_224736.jpg 20180814_224443.jpg 20180814_224916.jpg
     
    Paul Sutton likes this.
  13. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

    Interesting DirtyErnie. I think 5twins comments in Entry 3 above are very interesting regarding modern fuels. I never see the colors that the old plug color guides show and often the color guides are referenced as the result of 1000s of miles. On my SH with stock carbs my plugs look a bit like yours in the first picture after 2000 miles. The only thing I find that has an immediate influence on the color for around town riding is the mixture screw i.e. small changes of a 1/8 turn have a big impact on color. Like 5twins mentions, the choke at startup has a big impact which can be hard to clear away. See if you can get a photo right down in side the insulator. Remember that the color of the plug reflects how the engine was running immediately prior to inspection. If you run hard on the motorway then pull off and ride a couple of miles through town the motorway plug color will be obscured. I have yet to try the hard continuous run and kill the engine and roll to a stop. Still looking out for a nice place to try this.
     
    DirtyErnie and peanut like this.
  14. peanut

    peanut XS650 enthusiast & inveterate tinkerer Top Contributor XS650.com Supporter


    it may be my failing eyesight but those plug gaps look mighty big to me !?
    What have you set them to ? I always file the tip of the side electrodes on my plugs . Sparks like to jump from a nice sharp edge or point. Every little bit helps
     
    Paul Sutton likes this.
  15. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

  16. DirtyErnie

    DirtyErnie Renaissance Hick

    I don't really remember where I set these. Probably .035" or .045". I've tried opening them up until the bike stumbled, but that KungFu coil is no-$#!t! I couldn't get it to misfire at .065", so I stopped trying. The ride in this morning went pretty well. I think I'm going to try compensating for the throttle shaft leaks with a bigger pilot jet. Maybe experiment with some other needles. I'll post updated mileage numbers tonight. (I should really do my farm road mileage loop, 124 miles of 55 mph rural highway...)
     
    Paul Sutton likes this.
  17. DirtyErnie

    DirtyErnie Renaissance Hick

    Paul Sutton likes this.
  18. DirtyErnie

    DirtyErnie Renaissance Hick

    Commute is a little of everything, the last 10 miles before I get home is 40mph or less. But, the center of the plug noses was pitch black before this last needle move, with white rings bottom and top. Now it's all white. Something happened in a positive direction. The off-idle stumble I get, especially when cold, has me thinking I should go up a size on pilots and see how that goes.
     
    Paul Sutton likes this.
  19. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, a pilot jet size increase may be called for. That's often needed when you lean the needle setting. You said you dropped the needle all the way. How many steps was that from it's "plug blackening" position? One step can have a big effect, especially on plug color, so if you've gone several at once, that may be too much. Best you change (and test) by one step at a time.
     
    Paul Sutton likes this.
  20. DirtyErnie

    DirtyErnie Renaissance Hick

    one step from black insulator with white at the base & tip to a clean white insulator.

    Two steps from a black insulator with a slim white ring at the base to a clean white insulator.
     
    Paul Sutton likes this.

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