R100GS new driveshafts out of phase 5 deg

Discussion in 'Old's Cool' started by euromotorcycles, Feb 23, 2010.

  1. euromotorcycles

    euromotorcycles Been here awhile

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    I am replacing a R100GS driveshaft that was completely destroyed and could not be rebuilt . The new BMW DS is out of phase by 5 deg . BMW claims they are built that way .The bad one I just removed is also off 5 deg.

    Anyone here with more info on this .
    #1
  2. Airhead Wrangler

    Airhead Wrangler Long timer

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    Is that so they are IN phase when under load?
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  3. euromotorcycles

    euromotorcycles Been here awhile

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    That could be it since the oil heads DS when assembled are also slightly out of phase . I had a look at a recently rebuilt R100GS DS with the new poly damper and the phase is dead on. Would that be wrong?


    #3
  4. squish

    squish Out of the office.

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    Who at BMW claims they are built that way?
    Your local dealer, or someone on the other end of the phone at BMWNA?
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  5. folmonty

    folmonty Been here awhile

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    Euro - Just prior to sending my R100 drive shaft to HPMGuy this morning looked it over and you're correct. Seems odd but now hope it comes back the same way......:huh
    #5
  6. chiefrider

    chiefrider Chrome won't get you home

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    We have a local fabricator (Portland) who is gearing up to do rebuilds on these driveshafts with fresh ureathane dampner, cast IN PHASE.

    He installed a production prototype in his own GSPD and, for one thing, his mirrors are clear at all highway speeds.

    He is also doing some minor improvements to the bearings in the u-joints. I think he may have the best solution so far.

    The last time I held it in my hand, I discovered that my driveshaft is a bit out of phase, too. And I wondered if it goes "in phase" under load. Looking from the rear of the bike, the shaft runs counter clockwise. My driveshaft, if the rubber flexes at all, would be even MORE out of phase under load.

    Check this on your bike, keeping in mind the input torque and how it will load the rubber. I bet you will discover that this is your case as well!

    I plan to have him rebuild my next driveshaft.

    Tom in Salem
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  7. bereahorn

    bereahorn Long timer

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  8. Weaverman

    Weaverman Damaged goods

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    I just had HPMGuy rebuild my 32,000 mile R100GS driveshaft. It left here almost 4.5ยบ mis-aligned and returned aligned. In my case, adding torque from the engine would have increased the phase angle separation. I wondered if I would notice a difference in vibration level due to the increased durometer of the urethane damper. I did notice a difference; the vibration level is reduced across the range, as indicated by reduced rearview mirror excitement.

    I would also like to know who at BMW made the statement about the misalignment being intentional from the factory...interesting.

    Guy's work is very nice and his service is even better. Hard to imagine a better solution.
    #8
  9. motu

    motu Loose Pre Unit

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    I don't know about BMW's (I only own one),but having driveshafts out of phase is sometimes intentional.Early Nissan Skylines (and VL Commodores) had their driveshaft yokes out of phase by 15 deg.Of course mechanics who had them apart put them back in correct alignment...only to get a bad vibration.Sometimes these manufacturers know more than us...impossible as that sounds.
    #9
  10. Phreaky Phil

    Phreaky Phil Long timer

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    Interesting, I have an HPMGuy rebuilt driveshaft in my GS. One of my universals was starting to fail and the universals were out of phase. The rebuilt shaft is a great piece of work but I have never thought it is as smooth as the original. But changing tyres etc can have an effect on things so one would have to compare them back to back with no other changes.
    #10
  11. euromotorcycles

    euromotorcycles Been here awhile

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    Yes I did get this information from the dealer parts guy .The dealer at my request went on to check this out with BMWNA.The warehouse had 3 of them in stock . I was told they were all also slightly out of phase and probably built that way. No I do not have the BMW blueprints for those DS .

    I am intregeed with this and I thought that perhaps someone on this forum had the answer.

    There is a small car and truck parts remanufacturing plant that do driveshafts in my area they offer dynamic DS ballancing .I plan to have them check-out the ballance of that R100GS DS before I install it.I will follow-up on this later.

    #11
  12. jackd

    jackd Long timer

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    I was always under the impression that the oilhead drive shafts were manufactured slightly out-of-phase, whereas the airhead drive shafts were built with no out-of-phase condition. I actually read that here on this forum a few years ago and in other areas as well. Is it possible that the Dealer got his bikes mixed up?
    #12
  13. H96669

    H96669 A proud pragmatist.

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    Interesting, I have a brand new BMW driveshaft on my bench, that is a two piece one for my K1200RS. The closest I can phase it is still a few degrees off, and would be even worse under load also.:uhoh

    But FYI, the BMW shop manual for my bike does not even mention phasing the driveshaft upon reinstalling the rear drive, and neither does the Clymer's. I believe the original driveshaft failed because the previous "Mechanic" followed the shop manual and did not phase it. Also caused the tranny output and final drive input seals to fail.:confused

    Just last year there was an interesting article in BMW ON by Paul Greaves on "Driveshaft Phasing".:thumb

    I had my first BMW driveshaft failure in 1992, now my third one in 2009......in all those years you'd think that BMW could have improved on that well known "defective part" but.....I guess the accountants said no, let's keep selling them expensive replacement parts....!:(:
    #13
  14. x3300

    x3300 geoff

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    What are these improvements?

    -x3300
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  15. tailgunner27

    tailgunner27 GUNNER

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    Recently I noticed a small leak from the output shaft. Wonder if the tranny fluid could aid in a U joint bearing failure.
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  16. bereahorn

    bereahorn Long timer

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    I just last week installed the drive shaft on my '92GSPD with 35k which was overhauled by Guy at HPM. It was out of phase by 6 degrees and Anton had overhauled the tranny at just under 30K. I can't prove it but it seems to me the bike shifts better and feels smoother. I was concerned that the out of phase shaft might cause damage to the recently overhauled tranny so I bit the bullet and had the work done.
    #16