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How do you check if the alternator is functioning properly.

Discussion in 'Parallel Universe' started by EnderTheX, May 8, 2011.

  1. The Maz

    The Maz Clueless and lost

    Joined:
    Feb 14, 2013
    Oddometer:
    491
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    Medicine Hat , AB
    I think he meant when testing the output off the stator which is AC
    As in step seven of post#273
  2. GETTHUMPER2

    GETTHUMPER2 Been here awhile

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    Hi Wipe-out,,,I hope this makes sense,,,,THE DC SETTING is used when checking voltage at the battery terminals because the bike uses a "12-volt D.C. System", (ALL lights and electrical components with the exception of the alternator and voltage regulator consume 12 volt Direct Current, meaning that the electrons only flow in one direction).
    THE A.C. SETTING is used when checking the output of the 3 yellow wires coming from the stator because this electricity has not yet been "rectified" into DC current, that happens in the Voltage Regulator. The stator ONLY generates AC and the windings are always ISOLATED from ground, this is why you can only read resistance(ohms) between the 3 yellow wires themselves, and is also why you can only read AC voltage between the 3 wires and not from any of the wires to ground.
    All the best,
    THUMPER>>>>>>>>>>>>>>>>>
  3. sarathmenon

    sarathmenon Armchair Adventurer

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    The alternator puts out voltage in AC. That voltage is never sent straight to the battery, the alternator in all motorcycles is connected to a rectifier (that finned thing) which takes the three phase AC and converts it into a constant 14.4V DC. The 27V you see is normal, when you open the revs it should start going up in almost the same ratio. If you see 27V per phase at 1850 rpm, it will be roughly 55V at 3500 etc...

    Most importantly, are you seeing 27V across all three phases?
  4. GETTHUMPER2

    GETTHUMPER2 Been here awhile

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    Wipe-out,,,,,I believe your stator is "stuffed", your 1.5-1.6 ohm readings between the yellow wires should be less than 1, and more like in the range of .5-.8. The check to frame should be just like the test leads are not touching anything because the stator should be electrically isolated from the rest of the motor and bike, including the frame.
    THUMPER>>>>>>>>>>>.
  5. wipe-out

    wipe-out Been here awhile

    Joined:
    Jan 9, 2012
    Oddometer:
    520
    Location:
    Germany
    Thanks everyone for chiming in and helping to clarify. Took the new measurements from the connector with multimeter set on AC. Get different readings from all phases, I think in the order I did the reading:

    1-2: ~25V
    2-3: ~19V
    1-3: ~21V

    So I guess that confirms the alternator to be the problem. Now I just need to find a solution. Another rider on an F8GS just rolled in, he said he ALMOST carried a replacement :'(

    Gesendet von meinem E5803 mit Tapatalk
  6. wipe-out

    wipe-out Been here awhile

    Joined:
    Jan 9, 2012
    Oddometer:
    520
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    Germany
    Any thoughts on those readings? Because in one of the earlier posts by Joel Wiseman it says all should be above 18, which they are, but they are all different though.

    Gesendet von meinem E5803 mit Tapatalk
  7. sarathmenon

    sarathmenon Armchair Adventurer

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    If I had to guess, one of your stator poles is on it's way out. 19V vs 25V is almost a 25% drop. It's not fully dead yet, and you probably have another 1000 miles of life out it - the keyword here being probably :) If your next destination is somewhere away from civilization, it's worth fixing now rather than later.

    I'd suggest opening up the alternator case and at least visually inspecting what you see. if you are gentle in the whole process and have access to a gasket sealant, there is no cost to the whole process. The stator is right there on the case. If it's starting to burn out, you will see the evidence. If you follow the torquing steps in the manual, and use the correct torque for the bolts when putting everything back together, that gasket can survive multiple open-close cycles.
    ADVwxyz likes this.
  8. wipe-out

    wipe-out Been here awhile

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    Jan 9, 2012
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    Just a quick update, thanks to the greater ADV community a new stator will be on it's way from San Diego shortly, should have it on Sunday. May go ahead and attempt the repair myself, let's see. Meanwhile we're enjoying ourselves in beautiful Loreto!
    The Maz likes this.
  9. GETTHUMPER2

    GETTHUMPER2 Been here awhile

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    Congrat's in advance,,,I'm very sure that you can "remove and replace" the stator yourself, it is really not that hard of an operation.
    The KEY things to pay attention to are
    1. Keep track of ALL the bolts and where they came from because on many bikes they are not all the same length.
    2.Absolutely make sure that both mating surfaces are smooth and clean to eliminate any oil leaks
    3.The case cover will be stubborn to remove because the magnet of the rotor is trying to pull it onto the crankcase, just make certain that ALL bolts have been removed. Resist the temptation to pry the cover off , you will nick or warp the mating surfaces, often times a little gentle persuasion with a rubber mallet or a block of wood is all it takes to break loose a stuck gasket that is holding the cover.
    4. A new gasket is always preferred , however the old one can often be used in a pinch, if there are any breaks or tears they can be "mended" with a dab of nail polish.
    5. RESIST THE TEMPTATION TO USE ANY RTV SILICONE AS A GASKET MAKER, unless you know what you are doing, the chance of having bits of "squeeze-out" break loose as little silicone worms is high, if this happens it is VERY likely that they will eventually clog the oil-pump-pick-up and your motor will experience CATASTROPHIC-OIL-PRESSURE-LOSS. this often results in a seized motor.
    6. CLEAN all wire connectors and make certain that the actual terminals have a tight fit.
    7. TO PREVENT "COOKING" THE NEW STATOR,,,,,,,,change out the stock regulator to a series-style as soon as you are able to, I have had very good luck with the CE-605, my vendor of choice is Jack at RoadsterCycle.

    All the best,
    THUMPER>>>>>>>>>>>>>>
  10. dpike

    dpike BeeKeeper Supporter

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    thumper, do you have any pics of how you got that RR to fit where the old one was and wired up ?
  11. GETTHUMPER2

    GETTHUMPER2 Been here awhile

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    Sorry, no pics. the unit can be mounted anywhere that has airflow, in my case I relocated mine to just forward of my swingarm pivot, mounted the R/R to an aluminum plate as a heat-sink, and then bolted the plate to the frame. This was supposed to be a temporary install for easy access because at the time I was having many electrical issues, it has worked so well that I never bothered to move it.
    There are some threads here on the forum with some very detailed installs with good pictures/instructions and there is even a member that has made adapter plates for mounting in the stock location. If I run across them again I will post up the thread links.
    The wiring is VERY straight forward, 3 stator leads connect to 3 R/R leads, sequence is not important, there is a + R/R output lead that goes directly to + battery terminal and a -R/R lead that goes directly to the -battery terminal,,,,could not be any more simple..
    Best Regards,
    THUMPER>>>>>>>>>>>>>>>>>>>>>
  12. GETTHUMPER2

    GETTHUMPER2 Been here awhile

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    dpike likes this.
  13. wipe-out

    wipe-out Been here awhile

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    I have no idea what I'm doing, mediocre tools and of course I just got some RTV silicone. This is going to be fun.
  14. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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  15. GETTHUMPER2

    GETTHUMPER2 Been here awhile

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    Yes it can be, maybe better than 75% of wrenching is attitude/ mental, 15% skill/knowledge, and 10% tools.
    Tools can be borrowed/rented or ultimately improvised if you can visualize what has to be taken apart and what fasteners have to be accessed.
    In today's world, knowledge is just a click away
    Skill is and has always been something that is acquired through diving in and doing.
    ATTITUDE however is something that can ONLY BE FOUND within yourself.


    Me personally, I would rather see you patch/mend the old gasket or cut a new one from poster-board or even a cereal box before using RTV. Is it not possible to source a new gasket where you are??
  16. tofire409

    tofire409 Geared up and ready.

    Joined:
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    Oddometer:
    900
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    Toronto, CDN
    Another couple of options here: http://advrider.com/index.php?threa...5-regulator-for-2015-f800-gs-a.1117154/page-2

    I used JR's idea for location. I believe mine is 1/8" aluminum plate. I used the u-nuts from the OEM mounting.

    I have a SH775 RR from Jack. I'm coming up to 10,000km on it, 52,000km on the bike. I replaced the RR while I was still getting proper output numbers from the Stator.
  17. wipe-out

    wipe-out Been here awhile

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    Location:
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    Question for you guys: In the repair manual a couple of steps are listed as a prerequisite for removing a) the generator and then b) the stator. The one I'm not sure about is to make sure the crankshaft is in/at TDC (hope I'm translating from German correctly).

    Is this necessary to just remove the stator?
  18. sarathmenon

    sarathmenon Armchair Adventurer

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    No, that is for the flywheel removal, and needs a BMW special tool. The stator should be on the cover, magnetic and all that. Disclaimer: I have never opened it.
  19. wipe-out

    wipe-out Been here awhile

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    That's what I figured and what the pictures seem to confirm as well, just wanted to make sure.

    Removed the battery today to have it loaded and checked whether or not I have all the right tools. Good thing I did, because I didn't have a T27 which is needed to remove the engine cover. Found one in a local shop. Good to go once the stator arrives tomorrow.
  20. sarathmenon

    sarathmenon Armchair Adventurer

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    Note sure which instructions you were looking at, but here is a pdf from the factory manual with the pictures that should make the process more intuitive. The steps you need to follow are the ones for removing the right side case, removing the stator, installing new stator and installing right case. Ignore the steps in between that talk about the flywheel. The stator is on the case and not the bike.