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Thread: Cam tensioner gasket - '14 R1200RT

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    Cam tensioner gasket - '14 R1200RT

    BoxFlyer says I need to use a copper casket, I don't have that size but do have it in aluminum since it's the same as the oil drain. What is the reason for copper only? I wanted to check my cam timing this weekend before heading out on a trip.

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    Fortis Fortuna Adiuvat Omega Man's Avatar
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    Perhaps auto-correct gasket?
    I’m thinking you are looking for a copper “crush washer” gasket? I don’t know the size is but most of the chain auto parts stores have pretty good selections.
    OM
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    Liaison 20774's Avatar
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    Do you have the bike year and model? Helpful for finding the parts. I assumed a 2017 R1200RT and found item #5 on this diagram:

    https://www.realoem.com/bmw/enUS/sho...diagId=11_5170

    It lists "A20X24 CU"...the CU means copper. My guess is that the ID is 20mm while the OD is 24mm...looks like the thickness is 1.5mm:

    https://www.grease-lubrication.com/skf-flat-washer.html

    I googled "A20x24 CU" and find it used in a variety of devices...maybe some other sources are around?
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
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    Quote Originally Posted by strataj View Post
    BoxFlyer says I need to use a copper casket, I don't have that size but do have it in aluminum since it's the same as the oil drain. What is the reason for copper only? I wanted to check my cam timing this weekend before heading out on a trip.
    Sorry I didn't post the year and model it's a 14 R1200RT. Yes it's the copper 20 X 24 crush washer. Boxflyer says to use copper not aluminum, I was wondering why?

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    Liaison 20774's Avatar
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    Quote Originally Posted by strataj View Post
    I was wondering why?
    Who knows what the engineers were doing? Maybe the copper is better heat transfer? Better crushability? For something somewhat critical to engine operation, I'd be inclined to use the proper washer/gasket.

    I will change the thread title to include year/model.
    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!

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    Registered User cap's Avatar
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    The cam chain tensioner crush washer is A20x24x1.5 Copper, bmw part # 7119963342 and requires 30Nm of torque

    The oil drain plug crush washer is A20x24 Aluminum, bmw part # 7119963340 and requires 42 Nm of torque

    You can buy bags of both on eBay. Or order them by part number from places like BikeBandit. My guess is that the cam chain tensioner is copper because it achieves a good seal with less torque than aluminum.

    Cap

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    Thanks everyone! I got a response from a guru on another forum. He said the gasket ring thickness effects spring tension.

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    Registered User LFarling's Avatar
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    Quote Originally Posted by strataj View Post
    Thanks everyone! I got a response from a guru on another forum. He said the gasket ring thickness effects spring tension.
    Well I have pulled a bunch of cam chain tensioners in the LC bikes doing cam checks. At least 70 of them.

    That thickness makes no difference to that spring tension in the cam chain tensioner.

    I believe it is as stated above the copper crushes and seals at a lower torque then aluminum.
    Lee
    2017.5 R 1200 GSW

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    Fortis Fortuna Adiuvat Omega Man's Avatar
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    Quote Originally Posted by LFarling View Post

    That thickness makes no difference to that spring tension in the cam chain tensioner.
    I don’t think the thickness effects the spring either.

    Helge Pedersen, in the Globe Riders F800GS DVD, mentions that the crush washer can be “rejuvenated” in an oven.
    I can’t find an exact quote from Helge, but did find info from the Ferrari forum-

    One of the unique things about copper is that it "work hardens". You can see it do this if you've ever tried to bend a copper wire and then try to bend it back. Because of the work hardening effect, it actually gets stronger where you bent it so it will not bend back in the same place but somewhere nearby where its softer. This would mean that a hard washer wouldn't conform to surface irregularities as well and may not seal.

    Torquing down a copper washer and leaving it there can have this effect also. Annealing (heating to red hot and allowing it to cool) will reverse the effect so that the washer is soft again and can seal better. It can be done over and over again.
    https://www.ferrarichat.com/forum/th...-washers.3922/

    I think that if is so important, filter manufacturers should include it with the filter..........or at least train the “parts counter” to ask if you have a gasket while you are buying the filter.

    As an aside, I recently ordered a filter for the F800GS through MAX’s amazon portal. There was no provision to order the drain plug gasket but guess what- no need. Taped to the filter was the washer
    That’s the way to do it

    I guess for the years that changing the drain gasket was never mentioned (in the engine world), everyone was just lucky
    OM
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    Registered User cap's Avatar
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    Quote Originally Posted by Omega Man View Post
    I don’t think the thickness effects the spring either. ...
    Well, it does. You can prove it to yourself with a thought experiment. If the washer were a half-inch thick, would the tip of the cam chain tensioner be in the right place to touch the cam chain?

    So, the real question is, "Does the aluminum washer have a different thickness than the copper, after torquing?" And I think the answer is, "probably, but the difference will be so small that it won't affect the operation of the cam chain tensioner."

    See, that's the problem with making bold statements on the internet, in the presence of nit-picking engineers!

    Cap

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    Fortis Fortuna Adiuvat Omega Man's Avatar
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    Quote Originally Posted by cap View Post
    Well, it does. You can prove it to yourself with a thought experiment. If the washer were a half-inch thick, would the tip of the cam chain tensioner be in the right place to touch the cam chain?

    So, the real question is, "Does the aluminum washer have a different thickness than the copper, after torquing?" And I think the answer is, "probably, but the difference will be so small that it won't affect the operation of the cam chain tensioner."

    See, that's the problem with making bold statements on the internet, in the presence of nit-picking engineers!

    Cap
    Where did the concept of replacing a crush washer, be it copper or aluminum, with something a half inch thick come from
    I guess a suitably extended came tensioner could fix the extra difference the half inch made. Sounds like a lot of extra work.
    Must be out of the box of nit-picks
    OM
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    Registered User LFarling's Avatar
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    Yes I do think it would be in the same place. It is a spring for gods sake. It will adapt to 2 microns of thickness!

    It is oil pressure that holds the tensioner not spring tension. Come on guys it does not matter which you use but I do advocate using the correct crush washers it is not that big of deal.

    Again people applying human traits to metal parts. That cam chain tensioner could care less if it is a copper washer on it or a aluminum or nothing at all. It will not affect the cam chain tensioner one bit.
    Lee
    2017.5 R 1200 GSW

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    Quote Originally Posted by strataj View Post
    BoxFlyer says I need to use a copper casket, I don't have that size but do have it in aluminum since it's the same as the oil drain. What is the reason for copper only? I wanted to check my cam timing this weekend before heading out on a trip.
    I did my cam timing this weekend thanks to Cap, Lee and Omega Man and for sure not to leave out BoxFlyer! The bike a 14R1200RT has over 36,000 sMiles.

    Lee please note the cam timing was off a little on both sides. I heated the copper gaskets and with cleaning them up was able to reuse them, no leaks. I've order new gaskets if I do others or recheck mine. One tip is to be sure you have a 16mm torque adapter https://www.mactools.com/en-us/Wrenc...orque-Adapters - my 16mm crowfoot didn't work, not enough reach.

    BoxFlyer's video was of great help (Thank you BoxFlyer!) but I need to mention one error. The torque on the cam nuts is 65Nm per the BMW Repair DVD.

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    Registered User cap's Avatar
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    Quote Originally Posted by strataj View Post
    ... One tip is to be sure you have a 16mm torque adapter https://www.mactools.com/en-us/Wrenc...orque-Adapters - my 16mm crowfoot didn't work, not enough reach...
    I also spent $30 for a Snapon 16mm torque adapter... and then Boxflyer told me that he uses a 5/8” torque adapter which is the same as 16mm .... much cheaper. D’oh

    Glad to hear it went well. I find that the most confusing step is setting the cam position sensor. There’s a line and a notch that must be aligned. But not the center of the line to the center of the notch. Very strange. I suspect it doesn’t make a difference as long as you’re close, and consistent from left to right cylinders. How did you do it?

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    Quote Originally Posted by cap View Post
    I also spent $30 for a Snapon 16mm torque adapter... and then Boxflyer told me that he uses a 5/8” torque adapter which is the same as 16mm .... much cheaper. D’oh

    Glad to hear it went well. I find that the most confusing step is setting the cam position sensor. There’s a line and a notch that must be aligned. But not the center of the line to the center of the notch. Very strange. I suspect it doesn’t make a difference as long as you’re close, and consistent from left to right cylinders. How did you do it?
    Yep 5/8" is the same as 16mm but didn't check a cost difference. I didn't know the details you describe concerning the cam position sensor so I lined it up to center. It seems to run fine. If it's off would it effect the stick coil at some point? How do you line it up if not to center?

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