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Thread: What do you think happened?

  1. #1
    Robert E
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    What do you think happened?

    I have a 1978 BMW R80/7 that I have owned since new. This bike has approximately 75,000 miles on it. The transmission has developed a loud whine when in 3rd gear between 4,000 and 5,000 rpms. No grinding.

    I have always serviced the transmission regurlarly ( at least every 10,000 or so miles) and I have run sythetic gear oil in it for at least 15 years. The last time I serviced it I used Royal Purple brand before that Mobil 1.

    I am not hard on the bike but I am curious why 3rd gear instead of 5th gear where the bike spends most of its time. When I ride this bike it is for long distances such as Texas to Alaska or Texas to Canada. My question is; what is going on inside of this transmission and what do you think the fix will be?


  2. #2
    Liaison 20774's Avatar
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    Did the sound suddenly appeared, maybe a result of a recent fluid change? What's changed?

    Is anything showing up on the magnetic drain plug during servicing? At most you should see a fine oil dust when you roll it between your fingers. If it starts to include larger "chunks", then it's time to have it looked at. I'd consider riding it until you start to see more debris on the plug. Or get better ear plugs...sorry, not funny...

    For my money, 4-5K in 3rd gear seems high. I'm in 5th gear by 4K RPM but then I'm a wuss.

    Sorry, I don't know enough about trannys to offer any advice on what's making the sound. I also run Dino oil so that's no help, although I have about the same mileage on my '78 R100/7.

    Kurt in S.A.

  3. #3
    Registered User 88bmwjeff's Avatar
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    Has the tranny ever been rebuilt? At 75,000 miles, it's probably due. I would watch and check the drain plug for any metalic particles, that's not smooth. I'm assuming you have a magnetic plug. Material on the plug is normal, but it should feel silky smooth between your fingers. Any grittiness is not OK. If you don't have a magnetic plug, get a small telescoping magnet and stick it in the fill hole to see if you pick up anything off the bottom.

    BTW, if there is gritty material noted, then it's time for a rebuild (bearings, springs, and seals).
    Jeff in W.C.
    1988 R100 RT (the other woman)
    "I got my motorcycle jacket but I'm walking all the time." Joe Strummer

  4. #4
    Robert E
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    I have it at MPH Cycles in Houston right now. They are going to tear into it. They specialize in the old BMW's and Moto Guzzi's. I didn't want to ride it until it destroyed itself. It has never been rebuilt or had any problem whatsoever. I put in a new clutch assembly at 60K.

    I bought the bike new in Austin at the BMW dealership; but they no longer work on older Airheads.


  5. #5
    K Bikes Complex by Choice cjack's Avatar
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    Quote Originally Posted by easter85
    I bought the bike new in Austin at the BMW dealership; but they no longer work on older Airheads.
    That's understandable, but unforgiveable in my opinion. BMW is even offering an additional on line course to their mechanics for the older bikes incl the airheads.
    However, repair bills sometimes run high and owners often are highly critical. Too many buy airheads because they want economical transportation. Unless you do the work yourself, they are anything but economical. All this when the dealer could be using the time to do service on the 10 LTs waiting in the service bay.
    R1200GS LC Rallye
    Jack Hawley MOA and RA #224, KE9UW ("Chuck")

  6. #6
    Registered User boxerkuh's Avatar
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    I hope that the dealer will find the problem. 75K is not alot of miles on the bike. It is hard to diagnose problems over the internet. Question is was this sudden? Did this happen after an oilchange or are you due for one? I am not a mechanic, but I am learning. I probably would have done a simular thing, but flushed the fluid and taken the tranny out and shipped it off. That would save a little money. Please let us know what you find out was the cause. I disagree that with 75K a tranny is in the area of requiring a rebuild. Knock on wood, I have over 88K on mine and continue to change fluids every 5K. I have noticed that is works a lot smoother with new fluid. So, waiting every 10K maybe a little far apart....
    My food for thought...
    Keep the rubber side down!!
    1986 R 80 RS
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  7. #7
    Robert E
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    I don't know if it was sudden because I am very hard of hearing. When I began to notice it; I thought maybe that I was just keying in on the noise and that maybe it had been there all the time. But, when Mike Haven rode it at MPH Cycles; he said it was loud and it wasn't normal.

    I was kind of surprised myself as I have always used the best gear oil available and changed it anywhere from 5,000 to 12,000 miles. However it was manufactured in July 1977!


  8. #8
    Registered User Rinty's Avatar
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    what happened

    Easter:

    Since your transmission is probably going to be disassembled, you have the opportunity to install the updated version of BMW's cam selector plate, which will give you more positive shifting. The upgraded shifter system was sold as a kit under part number 23-31-90560150 for $65, but this was a while back. Also ask your tech to replace the little return spring in the tranny with a new one, but I assume he will do that as a matter of course, along with a drive shaft spline service, before everything is buttoned up.

    Rinty
    Last edited by Rinty; 04-08-2006 at 04:11 PM. Reason: replace word

  9. #9
    Robert E
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    Will do.

    Thanks Rinty.

    Robert E.

  10. #10
    Polarbear Polarbear's Avatar
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    R100/7 owner here.

    I bought my R100/7 in '78 and still have it with 280000 on its clock! I did my own tranny at 60000 miles ( gear mechanic at the time ), because of what a good friend Beemer mechanic told me was excessive bearing noise in mine. I worked in the business, so tearing into it myself seemed right. I had no difficulty, as a seasoned wrench. Special tools come in handy, for sure! I don't recommend doing your own and I don't think anyone here suggested such, but one could get through the task with a reasonable mech. background. My point! These older bikes are so well built, they will no doubt outlast anything new BMW is building(IMO). Don't fret too much over your /7. I have 220000 miles since I did my own rebuild and use strickly 90w dino gear oil(StaLube) GL5 rated and at between7500/10000 miles, or before every very long trip! My parts replaced; all bearings, cluster gear(5th was very slightly pitted) and fifth gear on the main, noth'in else. I towed a trailer around the states in 1980 and figure the stress probably wore fifth gear prematurely, however minor. It still shifts like a dream and I figure it will outlive me. Happy Trails...PS; I bought this bike on Valentines Day '78...Could never sell it!

  11. #11
    Robert E
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    Polar Bear.

    I am not stressed about it as long as the mechanic knows what he is doing and he should since I have been a customer of his off and on for about 20 years and he has a long Airhead background.

    I am curious to know what happened; and maybe after they get it open they will be able to tell.

    As far as longevity of these old bikes I agree. I would never sell mine. My bike has taken me to Hell and back many times and even when it wasn't doing great; it brought me home.

    I bought a pristine low mileage R1100RT and I literally hated the bike from the moment I got it. It was total disappointment. There was absolutely nothing I liked about that motorcycle except the way it looked. It and I were just like 2 dogs that looked at each other and immediately wanted to fight. I could list all the "goofy" things about that bike but I don't want to write a book. I put 2,000 miles on that bike and sold it. I am all about function; and that motocycle was all about style.


  12. #12
    Polarbear Polarbear's Avatar
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    Good luck to ya!

    I feel same about my oldie. My newer KLT is alright and I will hit 100000 miles on it later this year. Only the second beemer I've hit the 100K mark on. I've had a few others get very close but never over the mark. My R100/7 at 280 now has simply amazed me and others I tell when I travel with it. I keep it in really good condition and its able to go anywhere anytime. Sorry your K experience was so poor. This KLT seems to keep my interest, but could never replace its older cousin. Happy trails. PS; You wanna hear some other neat stats? My R100 has original valves, original front wheel bearings, rear bearings have 260000 on them, original steering head bearings, original alternator, diode board, bored cylinder(bigger pistons), and so on. It is quite a conversation piece, imo. I may ride it to Vermont Rally. Whats another 8 thousand miles? None off the above original parts seem to wear and have been extremely well cared for. Another day!

  13. #13
    Robert E
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    Polar Bear. My other bike wasn't a K. It was an R1100RT.

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