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Thread: R75/5 not smoothly shifting 2nd to 3rd

  1. #16
    Liaison 20774's Avatar
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    I'm not a petroleum engineer and don't really know any. But 140w is still 140w oil. It's not coming near my bike!
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  2. #17
    MOA #24991 Pauls1150's Avatar
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    Not necessarily, Kurt - the mutigrade synthetic (like 75W90 or 75W140) flows a LOT more easily than a straight petroleum 140W would.

    Mutt never mentioned what the mileage is on his bike... maybe it needs to be re-shimmed? The master mechanic (Jed) at Marty's re-shimmed my 2nd /5, and from then on, it was SWEET!

  3. #18
    Liaison 20774's Avatar
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    Quote Originally Posted by Pauls1150 View Post
    Not necessarily, Kurt - the mutigrade synthetic (like 75W90 or 75W140) flows a LOT more easily than a straight petroleum 140W would.
    How so? The base or "winter" value is 75W versus the recommended gear oil at 80W. Can the 75W flow that much better?? I'm just concerned about the additives that give the oil the 140 weight at the upper temperature. For me, I'll just stick with the OEM recommended lubricant.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #19
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    Thanks for the responses on the Red Line stuff! I will be spending a little time over on their website....

    I'll report back once/if I try something from their line up.

    ECJ

  5. #20
    BMWMOA #24809 jhall's Avatar
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    Quote Originally Posted by ecjjce View Post
    Thanks for the responses on the Red Line stuff! I will be spending a little time over on their website....

    I'll report back once/if I try something from their line up.

    ECJ
    It's amazing how far lube technology has came. Don't need an engineer degree, just read the info on RedLine's web site. I would not even consider 140 wt dino oil, as it would pour like molasses. But there's a world of difference between dino oil and quality synthetic. The RedLine 75W140 pours like dino 90 wt. Will see how it works, down the road. According to many, I can only expect 60,000 to 80,000 miles out of the gearbox before rebuild anyway. The same people highly recommend dino oil. With 40,000 now on this Airhead, I am half way there. Time will tell how the RedLine works out.
    Last edited by jhall; 05-05-2021 at 01:24 PM.
    BMWMOA #24809

  6. #21
    #4869 DennisDarrow's Avatar
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    If you will listen to folks who have actually been there and done that, walked the walk and not just talked the talk.........It's a common thing, if maintenance is performed as it is supposed to be done, for the /2 and above to go 100's of thousands of miles. It is just maintenance and riding with a style of trying to make the machine last rather than seeing how quickly one can wear it out...........Just thinking about how learning to shift a particular type of machine the way it asks the rider to shift goes a lot further than the type of oil......just thoughts......Good luck........Dennis

    When YOU are in N.W. Georgia, find your way on Hwy 136 outside of Calhoun, to my mountain top. Camp or RV awhile up on top of the hill and find the peace that I do..........God bless

  7. #22
    Liaison 20774's Avatar
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    It is my understanding that an 80w or 90w gear oil has about the same viscosity as say 40w engine oil. They must measure them on a viscosity scale or something.

    I'll probably jinx myself, but I have 110K on my /7 using 80w90 gear oil since I got the bike. I'm experiencing no issues with the transmission or drive line. From what I've read from people like Tom Cutter and Oak, I'm likely nearing a point of considering a transmission overhaul, but for now, I'll just keep riding.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #23
    Registered User STEVENRANKIN's Avatar
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    Viscosity

    Part of one of my jobs was to measure viscosity of liquids. A viscosity meter is used, viscosity is viscosity, a fluid that pours like molasses has a high viscosity whereas water has low viscosity. The numbers are the numbers.

    I have been running regular gear oil in my R80RT for 240K miles, and have never had the transmission apart even for inspection. It works, it works perfectly fine. I expect it to out last me.

    Same goes for the engine, I have been using standard 20w50 oil, best quality approved for air cooled engines for the same length of time. Crank bearings, cam bearings, cam lifters, connecting rods, all main bearings are original at 240K miles.

    I follow the recommended fluid change intervals.

    I would have to ride an exact same model bike set up exactly the same way with the exception of synthetic gear oil in one bike and regular gear oil in the other to see if I could tell any difference in gear box operation. I have no desire to go out and experiment. Mind you, I have had my RT since new so I know its transmission's history well.

    Could it be the change over to synthetic oil by second owners isn't really any better than just changing the gear oil in a new to them bike? I mean, who knows what a previous owner ran in the gear box, or when they changed it. Unless of course a person knows the PO very well or has maintenance logs. It is a gamble the old gear box oil was sludge.

    Just my two cents, I know what has worked and still works in my two airheads, now in my cars, of course they are new enough synthetic oil is called for. Different fish. St.

  9. #24
    BMWMOA #24809 jhall's Avatar
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    High Mileage

    It is encouraging to hear of Airhead transmissions lasting 100,000 miles or more. It seems some last longer than others, and those who predict early failure are also in the repair business. A few GL1800 GoldWing transmissions fail at 4000 miles, but millions last over 200,000; I suspect it's similar with Airheads. If I look back since my first (of six) Airhead(s) in 1981, I have ridden them collectively over 200,000 miles, and closer to 250,000. I only replaced two transmissions, and pretty sure both were in the first Airhead, a 1978 R100/7, which I rode about 140,000 miles. Back then, good used transmissions were plentiful, for $50 to $100. So I simply swapped in a 'good one' each time. I didn't even save the old ones, just tossed them in the scrap metal. None of the other five Airheads had over 100,000 miles when I bought or sold them, and none needed a transmission while I owned them.
    I have only owned 5-speed Airheads, 1976 through 1995, and don't recall any special operating procedures required. Any transmission that must be 'babied' in any way is not for me. If it must be double clutched, throttle blipped, or 'played with' in any way, it's a safety hazard and must be fixed.

    For gear oil, I recall the 1980s when a molybdenum additive was recommended by BMW gurus, and I used it faithfully; later, oil became available with molybdenum already added, which was more convenient. The molybdenum was said to improve shifting and extend service life. So folks have been trying to 'improve' Airhead transmissions with oil additives for decades. As for modern synthetic oils with additive 'packages' included, using it for about 20 years now (in other applications) I have found it to be one of the easiest, cheapest, best things to improve any transmission, even if already perfect. It simply makes a good transmission better. I have never experienced leaks or premature failure with it either. Don't knock it if you ain't tried it. LOL

    STEVEN you said 'viscosity is viscosity', and I agree. But multi viscosity oils continue to evolve, and make the conversation more interesting!
    BMWMOA #24809

  10. #25
    Liaison 20774's Avatar
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    jhall -

    A bit off track, but what year is your Airhead? Is it outside the window of the missing circlip in the transmission? Snowbum has it covered as does Anton. Seems it began with the '85 models and ended with the '94 models, maybe slipped into the '95 model year.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  11. #26
    BMWMOA #24809 jhall's Avatar
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    Serial Number & Cir-clip Fiasco

    Quote Originally Posted by 20774 View Post
    jhall -

    A bit off track, but what year is your Airhead? Is it outside the window of the missing circlip in the transmission? Snowbum has it covered as does Anton. Seems it began with the '85 models and ended with the '94 models, maybe slipped into the '95 model year.
    Researching this transmission serial number was early on my list, and it falls in SnowBum's category of most likely to be already installed. If repair is ever needed, will do the job myself, and check for a cir-clip then. Till now no symptoms, as described by Snowbum and others, have been noted. Thanks to RedLine, spline lube, a new cable, and cleaning & greasing all pivot points, the transmission is working better than ever!

    I have repaired several gearboxes over the years, including some that others describe as complicated. Don't see anything particular about Airhead transmissions, other than the Germans like to use tight fitting boxes, which call for heat to disassemble and reassemble properly.
    BMWMOA #24809

  12. #27
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    ShockProof_Tech_6.20_.pdf

    This is the Redline I used the last time I changed the transmission oil in my R100S. Bike had about 140K on it, changed clutch and serviced rear engine seals etc. Noticed seepage at seal at trans shift rod and had read about someone using Redline in their Airhead trans as well, did a little research and talked to some one at Redline through email, which I no longer have. I've been very pleased ever since.
    Dave Hutton '78 R100S (mfg 7/77)

  13. #28
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    Response from Red Line...

    In case anyone is interested, here's part of the (quick!) response I received from Red Line:

    "Thank you for contacting Red Line Oil, in your BMW transmission and final drive the V-Twin Transmission Oil/ShockProof Heavy would be recommended, these are the same products. This helps reduce the inherent clunk and noise, plus helps to find neutral."

    I'm going to try it out in one of my airheads (a 1979 R80/7), and will report back after I've run it a bit....

    ECJ

  14. #29
    #4869 DennisDarrow's Avatar
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    Quote Originally Posted by ecjjce View Post
    In case anyone is interested, here's part of the (quick!) response I received from Red Line:

    "Thank you for contacting Red Line Oil, in your BMW transmission and final drive the V-Twin Transmission Oil/ShockProof Heavy would be recommended, these are the same products. This helps reduce the inherent clunk and noise, plus helps to find neutral."

    I'm going to try it out in one of my airheads (a 1979 R80/7), and will report back after I've run it a bit....

    ECJ

    When YOU are in N.W. Georgia, find your way on Hwy 136 outside of Calhoun, to my mountain top. Camp or RV awhile up on top of the hill and find the peace that I do..........God bless

  15. #30
    BMWMOA #24809 jhall's Avatar
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    ShockProof Looks Great

    Quote Originally Posted by ecjjce View Post
    In case anyone is interested, here's part of the (quick!) response I received from Red Line:

    "Thank you for contacting Red Line Oil, in your BMW transmission and final drive the V-Twin Transmission Oil/ShockProof Heavy would be recommended, these are the same products. This helps reduce the inherent clunk and noise, plus helps to find neutral."

    I'm going to try it out in one of my airheads (a 1979 R80/7), and will report back after I've run it a bit....

    ECJ
    Considering your response from RedLine, and Kinterridge's experience with the same oil RedLine recommends (Heavy ShockProof 75W250), looks like the 75W140 I am running is comparable to their LightWeight, and is without the ShockProof additive (which, I am sure, is proprietary). Their Heavy version 'can be rated as a 75W250 gear oil' but flows like 75W90, impressive. Think I will jump on eBay and order a quart of Heavy. I see no problem with the 75W140 currently in the RT, but might as well go with Kinterridge's longer term experience and RedLine's official recommendation.

    Thanks!
    BMWMOA #24809

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