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Thread: Ignition Issues for 1982 BMW R65 (Videos Included)

  1. #1
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    Ignition Issues for 1982 BMW R65 (Videos Included)

    Fellow Airheads,

    This past weekend I spent all of Saturday troubleshooting and working on my 1982 R65 at the Culpeper, VA Airhead Tech meetup. I got to meet some awesome and passionate people. The tools and resources were insane:



    The main problem right now is the left cylinder is cold and not firing. Occasionally, the cylinder has pre-ignition and the ping is so violent - it knocks the carb off. The bike runs great but just on one side.

    If you look closely, the pings in the video knock the carb off yet the bike still is able to run.


    (sorry for the shakiness, the bike was vibing the phone)


    The bike has Mikuni VM34 Round Slide Carbs jetted at:
    Needle: 6DH3 | 3rd Slot
    Needle Jet: 159-P0
    Main Jet: AB180 -> moving to 210 (according to Bill @ Rocky Point Cycle)
    Pilot Jet: 35 -> moving to 40 (according to Bill @ Rocky Point Cycle)
    Slide Cut: 3.0

    We have eliminated the following problems:
    Valve clearances - set to 0.008|0.004
    Compression - 120 psi each side
    Leak down - no leakage
    Spark plugs - gapped and arcing
    Carbs - we switched LH/RH carbs and same problem occured - right side was firing and hot - left side cold
    Checked distrubtor & cap resistance
    Removed exhaust and checked for air flow

    More information:
    The bike was cranked over several times with the ungrounded and empty caps.
    The bike was able to idle and static timing was checked (with strobe light) on the left side.
    Is it possible to show 'S' for static timing on a side that isn't firing?
    When running 2-3k rpm, the right side would be close to ~2x hotter than the left side.

    Near sunset, we were advancing/retarding the Motorrad Hall Sensor and it felt like the left side began to fire a bit.

    Thanks to everyone at the meetup!

    Suggestions?

    -Andre

  2. #2
    got, got, got no time... rguy's Avatar
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    What coil are you running. The OEM coil is known to be very prone to failure. The hall sensor in the beancan can cause problems but it usually affects both cylinders. The Dyna brown coil is an excellent replacement. The Alpha ignition cured the last of my running problems.
    Good luck

    P.s. could be an air leak. Has the smog plumbing been removed and is the hole properly sealed on the head? Switch the spark plug leads on the coil towers and see if that changes anything.
    Neal - '16 R1200GS / '81 R65
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    I am running the Alpha Ignition System, there also is Brown Dyna Coils. Ill see what switching the spark plug leads coming off the Dyna coils does. Thanks!

  4. #4
    Registered User STEVENRANKIN's Avatar
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    Curious

    Just out of curiosity, do you have the stock ignition hall effect and module? If so, have you tried to go back to stock ignition?

    I say this because of your comment on rotating the hall sensor made a change. Perhaps the sensor is bad?

    I do not know the internal configuration of the Alpha sensors. Perhaps something inside is wonky? St.

  5. #5
    Quote Originally Posted by STEVENRANKIN View Post
    Just out of curiosity, do you have the stock ignition hall effect and module? If so, have you tried to go back to stock ignition?
    What, other than a hall sensor electronic ignition is a "stock ignition" on an '82 R65?
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://web.bigbend.net/~glaves/

  6. #6
    You already swapped the carbs so they are working well enough to idle at least.

    Switching the leads will verify if the problem is mechanical or ignition, just move the plug wires to the opposite side (you could swap the plugs along with to rule those out as well) If the problem switches sides then you can swap the plug wires at the coil end to prove out the wires and plugs.

    If it moves back then the plugs and wires are good and the coil and hall sensor are suspect.

    I think if the problem were at the hall sensor then it would have to be that the trigger shroud is damaged or bent, the sensor itself doesn't know which side it's firing it just does it's thing whenever the gaps in the shroud pass by. The possibility of damage to that is low but it's easier to see than how well the electrons are moving through the coil so it's worth a look before getting a new coil.

  7. #7
    Registered User STEVENRANKIN's Avatar
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    Opps1

    Quote Originally Posted by PGlaves View Post
    What, other than a hall sensor electronic ignition is a "stock ignition" on an '82 R65?
    For some reason, I thought they had changed the ignition system to a non BMW system.

    It does seem interesting the cylinder in question might have started firing when they were moving the hall effect can. St.

  8. #8
    got, got, got no time... rguy's Avatar
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    It seems extremely unlikely that the ignition is the problem since it fires both sides at the same time. Do the wire swap and eliminate the coil, plug wires and caps as the culprit. Swap the plugs too. Then do the "spray" test around the suspicious carb looking for leaks. Focus around the intake port. If still no luck you need to do a compression test looking for a bad valve perhaps.

    Edit: I see you did the compression test. Double check that smog port.
    Neal - '16 R1200GS / '81 R65
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  9. #9
    Registered User STEVENRANKIN's Avatar
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    What happened?

    Did you ever find what the problem was?

    I have not seen any activity on this post. St.

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    Update

    So last night I jetted the carbs to recommended specs from Bill @ Rocky Point Cycle, replaced the fuel lines (with nice cloth covered ones), replaced the 3D-printed rubber boots that go on the intake/exhaust of the carbs. I was feeling confident in the bike. The next thing, I checked for spark on both plugs. Then fired her up!

    Same thing - LEFT side was colder than the right side, heard some pings.

    Then I switched spark plug caps, cooled her off, and waited. While doing so, I noticed the RIGHT side was running lean (the plug was white and extremely hot). I only ran for about 2 minutes at 2-3k rpm. LEFT side had wet spark plugs.

    Once cool, I fired her up wuith the swtiched spark caps and guess what?

    The RIGHT side was now cool and I believe there was some pinging on the right side too.

    So I have everything dialed in from a mechanical standpoint. I am getting spark, but when I switch caps, the problem switches sides (I will do a couple more trials to be 100% sure).

    Does this mean something is wrong with my ignition coil?
    It doesn't make sense that I am getting spark on both sides though.

    I am currently running the Brown 1.5 Ohm Dyna Coils and the ALPHA Ignition System V.3. from Motorrad (that comes with a Hall sensor and control unit). Is it possible my control unit is messed up?

    Thank you guys in advance.

  11. #11
    Registered User STEVENRANKIN's Avatar
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    Forgive me for asking

    Forgive me for asking, does your bike have two separate coils, one for each side? Or is it one double coil?

    B0000274.pngB0000291.png

    Very much sounds like a bad coil or bad spark plug lead.

    Also, I am not crazy, I thought you had said you had an Alpha ignition on the bike.

    If changing the coil or spark plug lead on the bad side does not work, try swapping the hall effect back to stock.

    I found it interesting that you saw some firing when turning the hall effect unit.

    Thanks for the update, good luck. St.

  12. #12
    got, got, got no time... rguy's Avatar
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    The brown Dyna coil is a dual tower coil and is an excellent replacement. Sounds like a bad plug wire or cap. Are you running OEM? I like to run regular stranded plug wires with NGK 5000 ohm right angle caps. Avoid resistor wire.
    Neal - '16 R1200GS / '81 R65
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  13. #13
    Registered User STEVENRANKIN's Avatar
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    Problem Solved?

    Has this problem been solved?

    The thread has gone dead before the culprit has been disclosed. St.

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    Update

    I switched the caps around and even tested them on my buddies R65. Caps are good. Spark plugs are good.

    I then switched the spark plug caps on the coil-end. The problem switched sides, meaning the left side was firing and the right was cold. Switched it again (coil end), right side was firing left was cold.

    Does this mean the culprit lies in the coil?
    Is it possible to be in the Alpha Ignition Hall Sensor or the Module?

    Can someone please explain to me what the Hall Sensor does and what the Module does?

    How can I bench test the Brown Dynatek 1.5 Ohm Coil?

    Also, when removing the Dynatek Coil, I forgot to disconnect the battery. In general, when working with the electronics, should you have the battery disconnected?

    We're close, but I need your help!

  15. #15
    Registered User Guenther's Avatar
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    The Hall Sensor of the Alpha Ignition sends an electric pulse to the Alpha ignition module at TDC of either cylinder.

    From this pulse the Alpha Ignition module calculates the current RPMs and the necessary ignition timing for this RPM - so no mechanical advance.

    Both, the Hall Sensor and the Ignition module either work or are completely dead. It's "solid electronics"!

    I had early versions of the Alpha Ignition which didn't work "reliably" - which they did ALL THE time. The last version I got worked...ALL THE time.

    /Guenther
    2017 F700GS

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