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Points ignition maxed out

Discussion in 'The Garage' started by Jthomas, Sep 19, 2019.

  1. Jthomas

    Jthomas XS650 Enthusiast

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    I’ve been working on my buddies all stock 75’ 650.

    (I did not check the ignition timing first)

    Bike hasn’t ran quite right since he got it. I was checking out the mech advancer and found it stuck in full advance. The mechanism was pretty sticky.

    I had a spare (new) advancer setup for my 81 that I put in it. The parts looked the same to me.

    I go to check the ignition timing with a light after installing the setup. (I assumed the ignition needed some attention since this bike is pretty crusty and appears to be all original) The timing for each side was too advanced.
    -No big deal, I’ll just adjust it-

    Here’s the problem. I could not retard the ignition timing enough to get to the F mark. I was at least .500” advanced or so. On both sides. Couldn’t get it down any more.

    Idle was around 1100

    I checked the points gap. Set to .012”

    Attempted to set static timing- still can’t get the timing retarded enough. It’s very close static. But the adjustment is maxed out.

    The advancer shouldn’t have any effect on that, right?

    All the pins on the advance rod are correct.

    I can’t compare his bike to mine, because I have an electronic ignition. So other than the mech advance, nothing is alike.



    I start the bike to check full advance, and I watch the mark shoot literally to 10 o’clock. Wtf? And it idles back down to where it was originally set. Max retard is .500” advanced of F

    To clarify. Advanced of F. To the left of the F as if you were looking at it from the ignition side of the bike.


    What is going on with this thing.
     
    Last edited: Sep 20, 2019
  2. Jthomas

    Jthomas XS650 Enthusiast

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    3883C9A7-310A-4F89-BA00-DFDB52BF26C1.jpeg 3097B7CD-A893-44D7-A460-8104C1CCDCA9.jpeg

    954670F4-9EBF-4258-9B09-EF9630279190.jpeg

    See if anything jumps out at you guys
     
  3. Ratranger

    Ratranger XS650 Junkie Top Contributor

    How many miles? Maybe cam chain is really stretched, or possibly cam is a tooth off?. A tooth off is 20* at the crank. Easy way to check is get cylinder 1 to TDC with the advance mech off and the pin for the advance mech should face straight up at 12 oclock.
     
    gggGary likes this.
  4. 5twins

    5twins XS650 Guru Top Contributor

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    Did you lube up the advance rod real good so the advance easily returns to the retarded position on it's own? Just from the advance spring tension?
     
  5. Jthomas

    Jthomas XS650 Enthusiast

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    21k miles

    But I will check the cam position

    I did lubricate the rod. It all returns easily and smoothly on its own.
     
    Last edited: Sep 21, 2019
    gggGary likes this.
  6. Jthomas

    Jthomas XS650 Enthusiast

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    Hey sorry for the late reply.
    I removed the mech adv. assembly. Positioned left cylinder to TDC on compression stroke.

    The key on the cam (for the advance) faces 6 o’clock.
     
  7. Jthomas

    Jthomas XS650 Enthusiast

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  8. 5twins

    5twins XS650 Guru Top Contributor

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    That's fine then. With the pistons at TDC, the locating pin hole for the advance unit should face either straight up or straight down, depending on which cylinder is at TDC on it's compression stroke. If you gave the motor another full revolution (360°), the pin would then be pointing straight up.
     
  9. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Looking at your points plate, pic #1 in post #2, I'm not seeing an exposed gap left of the upper plate screw. Indicating that the plate can indeed rotate more CCW, retarding the ignition even more. Looks like the plate may be hanging-up on the screw's washer?

    As an example, here's the gap on the other side, indicating that this plate has been run to its advance position.

    PointsPlate02.jpg
     
  10. Jthomas

    Jthomas XS650 Enthusiast

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    Left cylinder @ TDC, cam pin points @ 6 o’clock
     
    Last edited: Oct 3, 2019
  11. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

  12. Jthomas

    Jthomas XS650 Enthusiast

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    I just removed the washers. I don’t gain any more movement. The plate is up against the screws that hold it down. (Out of adjustment)
     
  13. Jthomas

    Jthomas XS650 Enthusiast

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  14. Jthomas

    Jthomas XS650 Enthusiast

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    Yes, but is that correct? Should it face 12 or 6 on left cylinder.

    As of right now, it’s TDC compression on left cylinder
     
  15. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Well, grasping at straws here.

    Check the backside of the points plate for any protruding screws. Protruding screws will warp and cock the plate, making the points followers track funny on the cam.

    If there's a significant difference between the static timing and the timing light, suspect the timing light. We've had folks here with the newer units, and had the advance dial somewhere other than zero.

    If there's significant arcing at the points gaps, could be bad or disconnected condensers. Those may influence timing.

    Tweaks:

    You can file off a bit of the leading edge of the points' followers. That'll delay the points opening a bit.

    You can grind away some of the points plate notches, allowing it to retard more.

    *gasp*...
     
  16. Jthomas

    Jthomas XS650 Enthusiast

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    You may be onto something here.
    I recall one point arm throwing a pretty rowdy spark last time we ran it. (I didn’t know any better)

    How can I tell if the condenser is good? I have a DMM


    The static timing matches timing light. Too much advance, out of adjustment. Can’t retard far enough.
    Also. I trust my timing light, I verified it on my bike.

    Also. No screws on head were protruding and touching plate.
     
    Last edited: Oct 3, 2019
  17. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    At TDC compression on the right cylinder, the indexing pin will point straight up.

    In this rightside camshaft pic, notice the indexing pin hole, and the adjacent cam lobes pointing down, indicating that the right cylinder will be at TDC compression with the pin up.
    003.jpg
     
  18. Jthomas

    Jthomas XS650 Enthusiast

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    Okay then our cam is in time
     
  19. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    You can do the simple short/open test. But, the real test is "as installed", looking for sparks. You can swap the left/right condenser plugins, see if the sparking follows. If so, replace it...
     
  20. Jim

    Jim Beyond the edge, is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    Yeah.... right spring is under tension, left appears to be slack, or (almost) fully compressed. Possibly wrong spring on left? If it's not helping hold the advancer in full retard, it could be the right spring is being overpowered at idle, allowing full/more advance than it should.
    Untitled.png
     
    TwoManyXS1Bs likes this.

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