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Thread: Install larger 1981 oil pan on 1980 R65 ?

  1. #1
    kmcbmw
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    Install larger 1981 oil pan on 1980 R65 ?

    Bought the larger 1981 R65 oil pan on eBay with the idea to install it on a 1980 R65 that has the smaller capacity pan.

    Does anyone know if there would be any issue with doing this swap ? I expect I would need a different dip stick for an accurate reading. My main concern is that somehow the 1980 engine / oil pump would have some type of difficulty reaching the oil in the deeper pan.

    If anyone has done this before, or has words of warning I'd love to hear from you.

    thanks,

    -kai

  2. #2
    Administrator 20774's Avatar
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    Kai -

    You might want to check this website out:

    http://www.largiader.com/tech/oilpan/

    Seems to me there are a couple of ways to think about this:

    1) use deeper pan to lower the oil level in the engine to create more air space and less "windage" for the oil. This requires the longer dipstick but also requires an extension to the oil pickup. It's critical to get the pickup installed correctly. If it should come loose or allow air to enter, you don't get oil into the engine...not so good. You would still put the nominal 2 qts of oil in the sump.

    2) use a deeper pan to carry more oil and thus provide more of a chance for the oil to cool since more oil is traveling through the engine and potentially spending more time in the sump before being sucked back in. In this case, you don't need a new dipstick or a new pickup. You would fill the sump with more oil up to the point where it registers at its regular spot on the original dipstick.

    As Anton points out, what about clearance issues with the centerstand.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
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  3. #3
    shire2000
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    Well, you would need a longer pickup tube to be able to get to the oil.

    My question is why? Sure the larger pan will hold more oil, but those older bikes have run just fine for lots of years with the smaller pan. The extra oil is not really needed. The only real advantage I can see is you would be able to get maybe an extra couple thousand miles between oil changes, as it will take a bit longer to contaminate the larger amount of oil. But that is offset by having to purchase that extra litre or whatever amount more it takes.

    Myself, I would just rather change the oil more often, which is a good thing on any airhead.

  4. #4
    sumran
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    I put an '81 pan on my '80 R100. I did not do it to get additional capacity. I did it because of the barrier wall in the front of the pan. With the old pan I would get an oil light under hard braking. Not so with the new one.

    No new dipstick is needed as the max fill point is unchanged. the longer extension on the oil pickup is needed, but is a simple change. I did not change my centerstand when I did the pan and had no problems. I have since gone to a ride off stand.

  5. #5
    Rally Rat
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    Don't confuse R65s with the "big" twins. The 79 and 80 R65s use a shorter dipstick and shallow pan. The 81 on pan uses the same length stick as a /7.

  6. #6
    kmcbmw
    Guest

    thank your for feedback

    thank you everyone for your quick feedback.

    Sorry for the delay in responding, I was out of town re-doing
    the MSF rider safety course. Had been 12 years since I first
    took that class, and didn't realize how much I had forgotten.

    I'll update this thread if/when I install the larger pan.

    -kai

  7. #7
    VANZEN
    Guest
    Quote Originally Posted by shire2000 View Post
    ...My question is why? Sure the larger pan will hold more oil, but those older bikes have run just fine for lots of years with the smaller pan. The extra oil is not really needed.
    If not "needed", why did the factory invest to effect the same change ?
    (maybe, with the passage of time, they learned something)

    Quote Originally Posted by shire2000 View Post
    The only real advantage I can see is you would be able to get maybe an extra couple thousand miles between oil changes, as it will take a bit longer to contaminate the larger amount of oil. But that is offset by having to purchase that extra litre or whatever amount more it takes ...
    Two valid reasons for the deep sump were listed above by 20774,
    and neither involves surpassing the (finite) viable life-span of an oil:
    1) running a "quart low" with the extra volume capacity sump
    reduces crankcase pressure ÔÇô a very good thing in a horizontally opposed twin,
    which by nature of design is too efficient as a "pump"
    2) with the extra quart of oil, engine heat is dispersed into a larger volume reducing engine operating temps.

    #1 will be the more important and a better strategy IMO.

  8. #8
    shire2000
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    Still seems to me a fix looking for a problem.

    From my personal experience with Rs and R45 as well as talking to many other owners of these bikes, tie vast majority do not bother with changing to a larger sump. They just don't really need it unless you are constantly running at high revs in high temperatures. Many have ridden these bikes in stock condition, well over 150,000 to as high as 500,000 miles, with no ill effects.

    Simple Example, a very good Scottish friend runs a 1978 R45 with a Squire sidecar. Has owned the bike since new. Presently has over 350,000 miles on that bike. Bike is completely stock except for some minor frame gusseting to accommodate the chair. Regularly rides from England thru southern Europe to Egypt and back. Usually twice a year. Changes the oil and filter every 5000 miles. Never had to do anything to the engine internally, other than a valve job at around 275,000 miles.

    Another example is a buddy from Northern B.C. running his 1979 R65 totally stock. Has also owned his bike since new. Presently has over 200,000 miles on it and has yet to do any work on it other than normal maintenance. Regularly rides thru out Mexico every year, from roughly Sept. thru May. Then rides home to Prince George for the summer.

    So, I still see no reason to install a fix where there is no real problem.

  9. #9
    VANZEN
    Guest

    defining a need for us all

    Two points of fact:
    1) The BMW engineers apparently had some good reason to increase the capacity of the sump in 1980 (or 81, whichever it was),
    or BMW Corp. would not have invested the money to affect that change.
    The bean-counters would never allow it.
    2) An increased volume sump can provide very real advantages for a large displacement horizontally opposed twin.

    I am having problems with some statements that have been made:
    The claim that "it (a deep sump) is not needed" presupposes quite a lot,
    including the idea that someone has somehow evaluated, understood, and is willing to define everyone else's needs.
    To continue, the claim is supported by the anecdotal evidence of 3 or 4 individuals
    who's riding habits and experience have somehow not appreciated or needed this change ÔÇô
    evidence which does not refute either of the two facts listed above,
    or either of the valid benefits of the addition of a large sump
    (as stated in my previous post).
    Furthermore, the suggestion that the:
    "only real advantage I can see is you would be able to get maybe an extra couple thousand miles between oil changes"
    disregards the fact that any oil will degrade as a function of mileage and / or time,
    that the manufacturer specifies a certain rec'd change interval based upon the oil's ability to maintain it's design characteristics,
    and the fact that extending this change interval may result in serious detrimental consequences as regards engine longevity.
    By claiming the above as the "only real advantage I can see"
    also ignores knowledge of basic internal combustion engine operation and principles.

    And finally,
    at no point have I suggested that a deep sump pan is a necessity,
    or that everyone should have one.
    I have not even recommended it's use ÔÇô to anyone.
    Last edited by vanzen; 08-21-2009 at 02:04 AM.

  10. #10
    shire2000
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    Vanzen, I fully understand what you are saying. I am not attempting to "define everyone else's needs." I am defining the needs of the motorcycle in stock condition used as it was intended. One thing that most people do not understand is that the R65 and R45 were sold in very large quantities around the world. Of the over 65,000 R65 and R45 bikes sold around the world, only a small amount were ever sold in North America. The smaller engine bikes were built extremely strong and under stressed. I include the R45s as they share almost everything with the R65 except the pistons and barrels. These bikes are still used all over the world as daily riders in some of the most extreme and harsh conditions you can find, including extreme heat, sand and dust.

    The following is information supplied by BMW and published in Mottarad in 1980 on model changes for the upcoming 1981 model year:
    In 1981 the R65 and R45 received larger oil pans that allowed for .2 quart of oil more. The reason for the larger oil pan was the engine housing post was reinforced which changed oil ducts demanding a bigger oil pan. The oil pan was constructed with baffles to hinder oil starvation in extreme situations, such as extremely hard braking or leaning over to extreme angles to clear obsticles.

    For the vast majority of riders of the 29,454 R65s and 28,158 R45s produced from 1978 thru 1985, I still don't see any need to change out the smaller oil pan for a larger one that only holds .2 of a quart more oil. We are talking STOCK OEM oil pans here. Not the aftermarket ones. If these bikes have lasted this long without ill effects, why do it?

    If someone feels that the bike just has to have a bigger oil pan, go for it. It's their money. Just because the bike has lasted 30 years running the way it came from the factory is no testimony that it will last another 30 minutes. If they are really concerned about excess heat or oil starvation, maybe they should try contacting some of the people that have ridden these bikes in much more adverse conditions than most people will encounter riding in the USA or Canada.

    I stand by my comment: It is not needed for the vast majority of bikes out there. But will admit that it may be needed by some of the riders out there.
    There is an old addage that many do not seem to remember.
    Just because you can, does not mean that you should or have to.

  11. #11
    . AntonLargiader's Avatar
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    Quote Originally Posted by shire2000 View Post
    ... The reason for the larger oil pan was the engine housing post was reinforced which changed oil ducts demanding a bigger oil pan.
    Can you clarify that a bit?

    BMW continued to use shallow pans on the GS models to the very end, so the larger pan must not have been absolutely necessary.
    Anton Largiader 72724
    largiader.com bmwra.org

  12. #12
    Registered User lkchris's Avatar
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    Just to summarize ...

    Besides the new pan you will require

    1. Longer pickup tube

    2. New dipstick
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  13. #13
    Registered User lkchris's Avatar
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    Quote Originally Posted by AntonLargiader View Post
    Can you clarify that a bit?

    BMW continued to use shallow pans on the GS models to the very end, so the larger pan must not have been absolutely necessary.
    That's right it isn't "necessary" for the reason given.

    Interesting that (I think) the R80ST has the deep pan and the R80G/S has the shallow pan. Of course the pans on the G/S (and GS) are unique in that they contain threaded inserts for mounting the "skid plate." I've got the deep pan on my G/S, as I think the extra capacity is worth more than the miniscule amount of extra ground clearance (this isn't a "dirt bike" in any event).

    On the GS, of course, the oil cooler provides an additional 250cc oil capacity, which IIRC is similar to the extra capacity comparing the shallow and deep pans.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  14. #14
    VANZEN
    Guest

    + But will admit that it may be needed by some of the riders out there

    Quote Originally Posted by shire2000 View Post
    ...I stand by my comment: It is not needed for the vast majority of bikes out there. But will admit that it may be needed by some of the riders out there ...

    NOW, at least, we are on the same page ...

  15. #15
    shire2000
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    For further clarification.
    In the 1981 models the pan was made larger partially due to a change in the pickup heads. They went to a cast head that incorporated the spacer as part of the casting. The new cast unit has a spacer of approx. 15mm in length while the original stamped steel head used a 10 or 12mm spacer. Not a big difference, but enough that a deeper sump was required. This allowed for a whopping big 250cc more oil in the sump (about 1/4 cup).

    Here is a listing of the different pans over the years from 1970 on. Note the off road bikes (enduro) kept the smaller pan until 1991, but still did not go as large as the 1981-95 road bikes. One would think the off road bikes would require more oil due to the type or use those types of bikes tend to get, but BMW thought otherwise.

    External depth Volume Notes
    Front Rear
    38mm 21mm '70-'75, R65 through '80 (obsolete)
    40mm 19mm Enduro through '90, holes for bash plate
    55mm 29mm 1250ml '76-'80
    66mm 48mm 1650ml '81-'95 (not enduro), rearward-facing drain.
    52mm 32mm ' 91 and later enduro, rearward-facing drain, smooth bottom.

    As to dip sticks, you basically want to use one to match up to the appropriate pan. Here is a listing of the different dipsticks available. OA is the overall length in mm:

    Max Min OA Notes
    247 274 277 Metal handle, from /5. Superseded by "B".
    255 282 287 Metal handle, '76 and '77 models. Superseded by "A".
    260 282 287 Metal handle, from '78. Superseded by "A".
    263 284 288 "A" plastic handle, from '84 R65.
    247 273 277 "B" plastic handle, from '88 GS.
    256 274 278 "C" plastic handle, from '91 GS. Like B, but MAX is lower

    There were only 2 different pickup heads. The original stamped stell with a spacer and the later cast aluminum one.

    To further muddy the subject, many different aftermarket companies made deeper oil pans of various configurations. Some were just a deeper and bigger pan, some had extra baffles in them while others had weird configurations of tubes thru them for air to flow and cool the oil more. There has even been a few that incorporated an external spin on oil filter, which although a good idea, in practice was not. The filter was at the front of the pan and was in a perfect spot to get knocked off very easily. I think I remember Luftmeister also had one with an external oil filter that was remoted to a bracket bolted on to the frame, utilizing some rubber hoses.

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