Which is more reliable ... Points or Electronic Ignition for Airheads?

Discussion in 'Airheads' started by _cy_, Sep 17, 2012.

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Which is more reliable for Airheads ... electronic ignition or points?

  1. BMW Airhead electronic ignitions are super reliable. Leave it alone

  2. BMW Airhead electronic ignitions are junk, replace with aftermarket electronic ignition

  3. BMW Airhead electronic ignitions are junk, replace with beancan w/points

  4. BMW points & Condensers are reliable. leave it alone

  5. BMW points & Condensers are junk. replace with aftermarket electronic ignition

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  1. supershaft

    supershaft because I can

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    The twin sensor can sounds like a good idea IF just sitting there in the heat isn't just as hard on them as working in the heat. A friend put two in his and runs them both at the same time (no wasted spark).

    The beans can's biggest problem is the mechanical advance? I have worked and been around tons of bean can airheads since they first came out and I almost never see any mechanical advance problems. The problem I see them having is a failed sensor but that is the same sensor in what everybody else is selling so I hear about tons of mechanical advance issues since they have electronic advance. The trouble is I don't see much trouble at all with the mechanical advance. IMO, the easiest probelm to fix is one you made up to start with. How is a electronic advance going to improve starting over a mechanical one? If your bike is set up right, how would you get easier starting? Mine starts the second I hit the starter with a mechanical advance. Sorry but I just don't get it. :ear

    If I was running around the world, I would get a can that has a easily replaceable sensor and carry a spare. The biggest trouble will be remembering where you put it 20 years later when you need it.
    #61
  2. Bulldust

    Bulldust Bulldust

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    I don't understand how running two Hall Effect sensors at the same time would result in no wasted spark? It would certainly result in a distorted signal, no matter how accuratly they are mounted it is impossible to get the signals precisely at 180 degrees to each other.

    I see lots of mechanical advance problems, particularly on high mileage bikes the wear is a real problem, the bike still runs and starts but in comparsion to a modern electronic advance the power loss is very significant.

    "I hear about tons of mechanical advance issues since they have electronic advance". Not sure about this one?

    Advantages of a modern electronic advance over mechanical advance, everone who has tried my system has commented on the many advantages, I guess you would have to try them with an open mind to find out. If mechanical advance was so good why have all manufactures abandoned the system?
    #62
  3. chasbmw

    chasbmw Long timer

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    If you really need redundancy, then use either the Sachse or the Silent Hektik alternator mounted ignition and retain whatever ignition you have in the beancan position. Both these ignitions are reliable (I use both on different bikes) have a variety of ignition maps, some of which are suitable for twin plug use, and being mounted on the crank will not be affected by any timing chain wear anomalies.

    Changing over the ignition from one to the other can be done in minutes, I suppose you could make it switchable, but then sods law would result in having problems with the switch.

    Both systems mount the advance retard electronics Outside the engine so they won't be subject to too many heat cycles, which I think was the problem with the Omega ignition sold a couple of years ago. Volker Sachse also sell a variety of ignitions for laverdas, Ducatis and moto guzzis, his operation has a low BMW profile, I came across him via an aussi Laverda site!
    #63
  4. _cy_

    _cy_ Long timer

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    good point about difficulty of aligning up two sensor to trigger at exactly 180degrees. wiring two halls triggers together would defeat purpose of carrying spare halls inside beancan.

    does carrying your spare hall sensor inside beancan age at same rate as working hall trigger? spare installed Hall sensor goes through exact same number of cycles as working sensor. logic says odds of both sensor failing at same time would be remote.

    reason why mfg have switched from mechanical advance is to is lower costs and help pass EPA regulations. not due to mechanical advance failures. if mechanical advance failures was truly an issue, we'd be seeing it all the time on ADV and else where.

    running an aftermarket beancan with easily replaceable Hall sensor typically costs about $400. surely there's a way to modify OEM beancan to make changing out hall sensor field serviceable.

    seems there was someone that had multiple beancan failure due to magnets coming loose in Siberia. points beancan is starting to look better and better again. simple is good!
    #64
  5. supershaft

    supershaft because I can

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    Each sensor goes to one coil. No wasted spark. That's how you run a 360 or 180 degree crank with no wasted spark. Or you can have the same setup for dual plugging like some I know have done.

    Electronic is better and cheaper but that doesn't change the fact that I almost never see mechanical advance issues despite everyone and their mother on the net suggesting others might have them. Open mind? If I didn't have that I would have jumped on the sticking advance bandwagon decades ago but guess what? I don't see it. It's great when what I hear is what I see but . . . . And then there are the ignition curves available. With one exception so far, they don't empress me. I just dual plugged my bean can bike. It took about five minutes to readjust the curve from 6 to 28 degrees versus 32. I might delay full advance rpm in the future and that will take a bit more time but I can get the curve exactly where I want it. Not so with most electronic advances I have seen.

    I still don't know how advance comes into play at starter motor RPM? :ear
    #65
  6. Bulldust

    Bulldust Bulldust

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    When mechanical advance is stuck at full advance (as they often do) it makes the bike harder to start. I have had sticking advance weights in nearly all of my airheads, perhaps we just use them harder over here in Australia? I often see rusted internal parts inside original BMW beancans.

    As the hall effect sensors in the cam driven bean can are triggered every 180 degrees of crank rotation using two active sensors at 180 degrees apart in the bean can would trigger a pulse at every 90 degrees of crank rotation (as the cam/bean can is rotated 2:1 to the crank) seems to me that you would still have a wasted spark on each cylinder, and use twice as many sensors to do it. Also getting the two sensors mounted precicely 180 degrees apart is difficult unless you use an adjustable mount on one sensor.
    #66
  7. Airhead Wrangler

    Airhead Wrangler Long timer

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    Corrected.

    Your conclusion is right though. In order to trigger each cylinder once every 720 degrees of crank rotation, you'd need to make a rotor with only one trigger point on it instead of two which the stock one has. You'd also need one sensor to have a bit of adjustment to get it just right. As big as a PITA as that sounds, ducatis are like that.
    #67
  8. supershaft

    supershaft because I can

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    That's what I meant to say. I was getting my wasted spark setups and my dual spark setups mixed up in my head.

    Advances stuck on full advance? I work on quite a few bean can setups and I have never seen it. I have never had any problem with my 200,000 miles of personal bean can advance experience. I could find a nonop electronic advance and fix it with a mechanical one and claim they start better than electronic but what good does that do?
    #68
  9. _cy_

    _cy_ Long timer

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    worth repeating...

    electronic ignition failures in all but airheads are just about non-existent. yes all electronic can and do fail, but are very reliable.

    would we be having this discussion in say Honda or Yamaha bikes? yes ignition failures do exist, but for everything except for airheads they are rare indeed.

    someone will be along shortly to deny it all. but for some reason threads on electronic ignition failures for airheads both OEM and aftermarket ignitions consistently pop up.

    right or wrong, my take is due to location of halls sensor on airheads. Halls can fail early due to exposure to extremes in heat cycles.

    mechanical advances are very reliable, but do need maintenance. sure you can tear it down, but a shot of spray lube usually does it. little to no advantage with electronic advances. unless one is racing and need ability to change advance curves.

    your mileage may veri... but after much hashing... candidates for best solution are:

    1. stick with points with addition of ignition booster which reduces maintenance close to full electronics. carry spare point/cond, remove booster in case of failure.

    2. switch to electronic ignition with ability to field service halls sensor. beancans with two halls are still suspect because spare halls will be subjected to same heat cycles. carry spare halls in case of failure.

    due to high failure rates, 2x Bosch 12v coils should be changed out to a high performance Dynacoil. some OEM electronics last for 150k+ miles without issues. some are not so lucky... perhaps it's just time after faithfully working for 30+ years...
    #69
  10. supershaft

    supershaft because I can

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    Where is that you are getting your info. Electronic ignitions fail on all makes. Hall effect sensors are in hot spots in most motorcycle engines, not just airheads. I have been a car mechanic and worked at multi-line motorcycle dealerships. Other bikes DO have electronic ignition failures. Honda's or Yamaha's? Most of them are totaled long before most airheads. Go figure. And yes, electronic ignitions are still much more reliable than points.

    Brass floats aren't the answer either! :lol3
    #70
  11. _cy_

    _cy_ Long timer

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    yada.. yada ... yada... never said halls don't fail on other bikes and cars ... just that for what ever reason, they seem to fail more on airheads.

    if someone would offer a nice set of brass floats for bing carbs... I'd be all over em. and yes brass floats can fail too. but not like plastic floats. which can be counted on to give problems. vs brass floats rarely fail. then they can be repaired.

    in your dreams ... airhead electronic ignitions are more reliable than points... now if you had said less maintenance, I'd go for that until... you are pushing your airhead with a failed halls :lol3
    #71
  12. supershaft

    supershaft because I can

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    Just that for whatever reason? That's my point. Whatever reason you make up. Apparently from what you have gleamed from reading the idiotnet?
    #72
  13. _cy_

    _cy_ Long timer

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    yada .. yada .. yada ... ya what ever

    we'll see who's pushing their airhead first from ignition failure... your dead halls or my dead points....
    #73
  14. supershaft

    supershaft because I can

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    Just that for whatever reason? That's my point. Whatever reason you make up. Apparently from what you have gleamed from reading the idiotnet?
    #74
  15. _cy_

    _cy_ Long timer

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    yada .. yada .. yada ... ya what ever

    we'll see who's pushing their airhead first from ignition failure... your dead halls or my dead points....
    #75
  16. squish

    squish Out of the office.

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    First hand experience from someone who's a true believer of Electronic Ignitions...

    1983 R80ST, bad Bean Can to be replaced with A/M bean can.

    1993 R100GS Bad Bean Can replaced when the bike was still under warranty.

    1993 XR650L died, on the freeway (Carrying my wife) Trouble shooting lead to a failed CDI box AND bad trigger winding.
    Replaced the box and stator, (which also includes trigger winding) and problem went away never to return.

    1983 CB750F, Ignitor potting failed leading to Ignigtor failing. When the Ignigtor fails the bike no longer has Ignition.
    This mind you is an age and heat related problem, so an outlier when it comes to electronic ignition.

    But I've had far more experiences with points needing work and futzing and hard starting and...
    To sway me to go back to running points, ever.
    But I'm also a fan of fuel injection over carbs.
    #76
  17. GREWUPIN_D11

    GREWUPIN_D11 GREWUPIN_D11

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    1971 R75/5,rode it 4 years and 50k miles, never touched the points, no problems

    1984 R100RT, rode it 26 years, 40k miles, no (ignition) problems.
    #77
  18. Global Rider

    Global Rider Alps Adventurer

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    Do you mean more reliable or more maintenance free.

    Electronic Ignition is more maintenance free...simply because you really can't do anything to it.

    Points are more reliable...because I can fix them roadside and get going again. Try that with an electonic ignition module that has failed.

    And in both cases, they have coils, which can fail no matter what system you have.

    The last thing I'd want is "high tech" when riding in really remote areas.
    #78
  19. homere

    homere Been here awhile

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    Points are very simple, file / replace, ride, If you are going to put a electronic unit in, carry a set of points as a back up? They don't take up to much space.
    #79
  20. DaveBall

    DaveBall Long timer

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    I have had points fail in the middle of nowhere. The spare set I had would not work as they were bent out of shape from being the the bottom of my tool tray for umpteen years. So had a set sent to me via courier. Got them 2 days after ordering and was on my way.
    Had a bean can die up in the Yukon, back in 1993 while on my 81 RT. No dealers around with a bean can available. So had one sent via courier from Vancouver, got it 2 days later, installed myself and was back on the road.

    So, 2 days to get either a set of point or a bean can. Not a big deal to me. Sure, both were inconvenient, but not a trip breaker. Those were the only 2 times I ever had any sort of ignition issue in the past 35+ years of riding airheads.

    Both are extremely reliable. Points are more finicky and old school.
    #80