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Weird LED BPF Bulb Behaviour?

Discussion in 'Norton Commando Motorcycles (Classic)' started by Tornado, Mar 30, 2019.

  1. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    I've now tried three BPF type LED bulbs in my '74 850. First one seemed to perform fine for a few rides, then after checking high beam one night, noted it would not switch back the just low beam. Took it to bench and same issue...both sides of the LED bulb came on no matter which terminal I feed with negative power (these are positive earth type LEDs).
    I worked with the vendor (DynamoRegulatorConversions) in the UK and they sent me out a new, updated bulb (after many months being on back order). In fact I received two for some reason. Welp, both new ones seem to be doing the same thing...only full beam comes on no matter what terminal is feed negative power.
    Thought it might be something screwy in the Commando wiring/switching but why does this also happen in bench testing direct to battery?

    Here's the ordering page for pic and description:

    http://www.dynamoregulatorconversions.com/led-bulbs-especially-for-motorcycles-shop.php
     
  2. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    I think I've figured out why high beam is always on. Took the handlebar switch apart to check/clean contacts. Testing bulb using just dismantled switch by pressing contacts gave same situation. Tried removing high beam indicator bulb and then low beam could be on without high and toggling high/low worked correctly.
    So issue is the warning lamp must pass sufficient current along high beam pathway to allow high beam to turn on.
    I need to decide if a resistor or diode is needed in line to the warning lamp. I believe the bulb vendors sells something to prevent that warning light from being on with low beam, so that may be the solution.
     
  3. cyclegeezer

    cyclegeezer

    Joined:
    Jul 15, 2010
    Perhaps if the indicator bulb is also a LED?
     
  4. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Yes, that might be a solution. Will check with vendor and see what they recommend. I've no issue changing out the warning lamps. Both turn and high beam...my Assimilator warning have already be swapped to the SparkBright voltage indicating LED and Assimilator component binned.

    Now I'm stuck looking for one of the tiny screws holding the switch gear board in the cover...it fell out, I heard a metallic clank, then nothing further and have spent better part of one hour searching for its landing place. Looks like I'll need to drill/tap the fixture to accept a more readily available screw.
     
    Last edited: Apr 7, 2019
  5. lazyeye6

    lazyeye6 VIP MEMBER

    Joined:
    Feb 28, 2014
    The screw will show up in the middle of the floor next year.
     
    Tornado likes this.
  6. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    I have a chronic case of dropping small hard to replace parts. Sometimes sweeping the area with a magnet - especially the ones on the end of a telescoping rod - cures the condition. Also worth looking under things that are so far away that there is no chance the item ended up there. If all else fails sometimes doing the sweep up that you've put off for the last few months yields results.
     
  7. cyclegeezer

    cyclegeezer

    Joined:
    Jul 15, 2010
    I recommend disassembling the switchgear inside a plastic bag, the little buggers can't escape then.
     
  8. Danno

    Danno

    Joined:
    Feb 7, 2010
    <-----That is all LED, headlight,pilot light, taillight and gauge lights. The switch I'm using may have been a headlight switch or a blinker switch, I don't know. Got tired of fiddling with 4-position Lucas ignition switches and changed it to older-style off/on keyswitch. Everything comes on, but the headlight (both beams) only work if the blade switch is flipped one way or the other. If both were coming on at once, I'd suspect the switch.
     
  9. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Only works if the part is magnetic and the magnet is right on top/next to it!!
     
  10. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Never did find the dropped screw. Found. #4-40 screw at hardware store that seems to thread in OK.
    Went on a test ride with the LED headlamp on low beam...during daytime so can't comment of light output, but the SparkBright voltage monitoring LED shows much improved charge volts while riding amount town. With the incandescent bulb, indication was showing 12v or lower while idling near 1k, stopped at lights. Now it's showing 12.5v idling and quickly goes to good 13v charging range when blipping throttle to 2k. This was all with the high beam warning light pulled out to prevent the current leakage issue discussed earlier.
     

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