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Electronic Ignition - Less Vibration

Discussion in 'The Garage' started by Paul Sutton, Dec 19, 2016.

  1. xjwmx

    xjwmx It's just the unknown. Top Contributor

    "Back in the day" I was told that advancing as far as possible increased hp, and in fact those very high octane gas at the time were to allow you to advance the timing. Anyway, I did the retarding trick on my '81 and I recommend it too. There was no loss in power you could feel, but it was less prone to knocking.
  2. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Another take on this, is:

    "Ignition misfires" and "Ignition misfire percent"

    Google those. Been reading some articles on this subject, quite enlightening.

    Quote: "No engine fires every cylinder 100 percent of the time. "

    It's very likely that a high-energy electronic ignition would reduce the misfire percentage enuff to reduce vibration...
    Last edited: Dec 20, 2016
  3. Paul Sutton

    Paul Sutton Sprained Ankle Top Contributor

    xjwmx and TwoMany - The spark is not particularly strong. The transistor I will be testing as a replacement (ST901T) is claimed to produce a much stronger spark due to its characteristics. This transistor is easily available and is used in loads of small ignition systems. Regarding the retarding, luckily my 81 already has the screws on the pickup coils. I have also glued on a 6 x 0.5mm neodymium magnet and the postman has just delivered the timing light, so off I go.

    Thank you
  4. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    please do keep us in the loop with pictures!
  5. littlebill31

    littlebill31 Smells of Raw Fuel

    Does anyone have a couple pics of how to alter the '81 pickup to allow adjustment?
  6. Paul Sutton

    Paul Sutton Sprained Ankle Top Contributor

    I am also interested in an answer to littlebill31's question above.

    I have replaced the transistor and diodes. I did not see any significant change in the stability (very stable at idle) of the timing using the strobe. What did seem unusual to me was that as I increased the revs slowly the timing marker stayed at the idle position until about 2200rpm where it suddenly jumped to the fully advanced position and stayed there as the revs were increased further i.e. there was no indication of the advance ramping up as the revs increased. Also, when fully advanced there is a systematic firing taking place at approximately half the advance.

    Any thoughts? Will it be a Boyer Bransden this Christmas for my Wife?
  7. grizld1

    grizld1 Grumpy old man Top Contributor

    You don't need to alter the pickup, its mounting holes are slotted to allow timing adjustment.
  8. Tomterrific

    Tomterrific XS650 Junkie

    I think that neodymium magnet is much stronger than the original. This may be why you get a jump to the high speed pickup.

    I suppose someone mentioned this, the reason the electronic ignition is smoother is the replaced points were not set properly. Having both cylinders fire at the same timing is important. Same with having the carbs balanced. I set both points exactly the same at full advance. I also balance my stock carburetors both at idle and open throttle. The engine surprises me how smooth it is for a 360° twin.

  9. littlebill31

    littlebill31 Smells of Raw Fuel

    Thanks, Grizld.
    I got it now.
  10. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    Here you go bill. Like grumpy sez just change to screws, get rid of the potting and you are good to go. would be interesting to see how much timing range this gives

    Attached Files:

    littlebill31 likes this.
  11. Yes, the retarding works a treat.
    I had done that with my '83 in conjunction with xsJohn's compression mod. I recall the '83 had Phillips head screws mounting the pickup to the stator. Not so with the earlier TCI's? This engine that I'm running now in my '77 is either an '80 or '81......yeah, I could run the numbers but right now I don't care lol. The pickup on this stator was held on by those rivet thingies. I slotted them with a thin disc on a grinder and they turned out no problem with a large screwdriver. The stock setting was in the middle of the slot of the upper pickup mount, I retarded it as far as the slot would allow. I shot her with a timing light while adjusting but the timing tab on the stator doesn't have the "U" like 5twins pic shows in this thread.

    The results of the road test was akin to starting your day on a good cup of coffe instead of 3 espresso's. Same amount of work accomplished but without the BUZZ........
    She pulled strong, shifted good and seventy could have gone to eighty but for thoughts of self preservation.
    TwoManyXS1Bs, peanut and GLJ like this.
  12. cafetools

    cafetools XS650 Addict

    Hello. 5twins. I have a standard and I hear I should retard my timing slightly. Align the timing marks towards the right side of the F range? Which way does the points plate turn to retard? Right or left?

  13. 5twins

    5twins XS650 Guru Top Contributor

    Rotate the points plate in a CCW direction (so left I guess), the same direction the motor spins. This will make the points cam contact each points set a little bit later and that will retard the timing.
  14. cafetools

    cafetools XS650 Addict

    Thank you so much! I just want to be %100 sure about this. End result when setting the timing with the strobe is the lines will move to the right of the timing mark (f for fire)?
    And how much do I want to retard the timing to the right of the F mark? Is about 5 millimeters to the right of the F mark good?
  15. 5twins

    5twins XS650 Guru Top Contributor

    I set mine on the right slash mark of the idle timing "range" .....


    The idle timing "range" is 13°-17° BTDC. The "F" mark is 15°, the right slash mark would be about 13°.
    Last edited: Aug 19, 2019
    nj1639 likes this.
  16. Joe78xs

    Joe78xs 78xs650

    Hey guys, just a simple question (side bar) is pamcopete still around?? is he out of the bizz? I tried looking up the website got nothing.
    I know i have been out of touch for a while, just given myself a tune up an see whats going on. Thanks
  17. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    Pete closed his business.
  18. Paul Sutton

    Paul Sutton Sprained Ankle Top Contributor

    Nice photo there 5twins!

    If someone retards the timing too much they will lose power noticeably. This is a good self check to know when you have gone to far. If anyone wants another photo to show how much to retard by then search for the thread regarding an LED timing light by TwoManyXS1Bs:
    Oops, I have done the search already. In the first entry 2M has a video showing the timing light in action. If you look carefully you will see how much he has retarded the timing, especially when he revs the bike up - Thank you 2M.

    I retarded my timing and did get a smoother ride. Also, if you want to know what retarding feels like but do not want to mess with the timing then run your tank empty and fill up with a higher octane fuel. This has the same effect as retarding the timing.

    In the end I settled with about half the retard shown in 5twins photo and used UK Super instead of Unleaded Regular.
    Last edited: Aug 20, 2019
    TwoManyXS1Bs likes this.
  19. 5twins

    5twins XS650 Guru Top Contributor

    For me on my '78, because I'm still running the original advance unit, this is a precaution against over-advancing. As the advance unit wears, the amount it advances increases. So far mine is still OK, but I do throw a timing light on it occasionally to check it.
    Paul Sutton likes this.

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