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D.I.Y. Cam Chain Replacement

Discussion in 'Parallel Universe' started by Dieselboy, Sep 22, 2011.

  1. 211

    211 ThorsPadre

    Joined:
    Mar 5, 2012
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    166
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    Bellingham
    I'll be needing to do this soon (valves and cam chain replacement)

    Does anyone have a shopping list handy? I don't want to overlook anything.
  2. batica

    batica n00b

    Joined:
    Oct 2, 2020
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    3
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    Serbia
    Dear @Wacholek,

    many thanks for your at least "doctoral thesis" about tensioner. As I have the very same problem with stretched cam chain or bad tensioner, I have one question about it:

    Why did you make a new INNER piston, which is more complicated to be made than OUTER piston? I haven't found any words of this kind of solution...

    Regards from Serbia!!!
  3. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    I've offered speculation in the past that cam drive system wear would be much higher for the F800GS as compared to the F650/F700GS due to the considerably more radical cam grind of F800GS.

    As "supporting evidence" I offer this pic of my 2009 F650GS cam chain after 95K miles.
    The bike has had good maint. and oil changes, and while not abused, It has not had the life of the Starbucks queen either ....
    My Avatar is the inReach map of my latest trip - approx. 35K miles thru MX & Central America.

    Attached Files:

    bmwroadsterca likes this.
  4. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    I think these comments were originally made by @JoelWisman who is no longer with ADVRider.

    I'm going thru my notes tonight as I'm tearing into the topend of mine tomorrow:

    ~~~~~~~~~~~~~~

    1: The timing chain is NOT oil tensioned. If you look at the tensioner, oil pressure is not applying any significant force to the chain. The timing chain is oil damped.

    My theory about the chain failure is that the combination of a fairly radical cam profile combined with a super light flywheel combined with a longish cam chain is making the chain very susceptible to harmonic oscillations loading and unloading the chain multiple times per crank revolution.

    This theory was put fourth when my engine became the first to need to be pulled apart for a stretched chain and cemented when I inspected subsequent stretched chains at other dealers. A manual tensioner is not the way to address this IMO as they do much less to damp harmonic oscillation.

    A possible source of air ingress to the pressurized oil is an internal part of the gasket on the clutch cover, so don't reuse it, torque it correctly, and check the factories torque on these bolts as BMW is notorious for leaving things loose.


    2: The start-up death rattle is from oil drain back and subsequent filling in with air in the tensioner which bleeds rapidly. Not all oil filters stop bleed back as well as others and they do progressively poorer as the oil fills with more fine particulate. I do not believe this start up death rattle is material or important as long as you do not rev the engine while it is occurring.


    3: A stretched chain is easy to hear as initially it won't happen when the engine is cold after the first few seconds. It will not be present at idle for the first 10 minutes or so but will then become apparent. If you are real concerned, start up your bike and let it idle till the cooling fan cycles on and off several times. If you start hearing a rattle towards the latter fan cycles, your cam chain is stretched. It is the only component that rattles only once the engine is hot hot but initially at no other time. The rattle is completely unmistakeable, anything short of a deaf guy will hear it and know it can't be right.

    4: You measure chain stretch by taking the end off the chain tensioner and measuring how far you can force the puck in before it tensions the chain. I used to have measurements in my desk but they were lost when I was terminated without warning. Someone who has a new chain will have to measure this, then someone else who's chain is rattling when hot hot, then we will have measurements. To date, BMW does not specify any way to measure chain stretch.


    5: I am glad it is someone else trying a master link as I wouldn't want to be the first :) There won't be any issue with clearance that I can think of, but the extra weight may or may not contribute to chain oscillation.


    6: I don't know how much it matters, but many ham fisted BMW techs break the top chain guide towards the exhaust while removing the cam cover for seal replacement or valve adjustment. The wire harness is totally in the way when removing the cover and the exhaust side top guide takes a hit if the tech or owner isn't careful.

    I took loads of grief from techs and the service manager when I wouldn't let techs pull the broken piece out and ship the job since what the customer doesn't know won't hurt him.....

    Eventually my old shop started stocking that piece as it was always in Germany and customers weren't happy when we pulled the cover to do an adjustment, then had to keep the bike for a few weeks waiting for the part.

    I am friendly with many other shops and have heard them comment on this part being broken as well. Some replace it, some pretend nothing ever happened cause they like my service manager figured it wasn't important.

    I don't know how important this part is, but I have to believe BME put it there for a reason and it is even possible it is leading to some of the early cam chain failures.

    I have since had the cam cover off on 2 F8's I helped friends service, and both had old discolored broken exhaust side top chain guides.

    This may or may not be an issue but it is sure something to watch out for.

    7: If a manual tensioner blocks the oil flow through the tensioner cavity, you will loose the cam in a hurry.

    8: I think the cam could twist the water pump shaft in half without stretching the cam chain at all. I don't think the water pump is related to any of the F8's cam chain woes.

    Just my thoughts but helpful perhaps?
    Zoef zoef and Duitser like this.
  5. Pallisti

    Pallisti Adventurer

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    Number 7. Does the oil flow through the tensioner to the cams? If you ask me it would be silly to run the large amount of oil that the top end needs through such a small hole.
  6. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    I have my cams and cam holder laying on the table just now so it's fresh in my mind.

    It certainly appears that all the oil is delivered to the head thru the one gallery that comes up past the tensioner.
    The "outlet" hole at the cam holder is perhaps 5/16" (just guessing - I didn't measure it).

    The 1st bearing on the cams are cross-drilled and use slotted journals for continuous flow to the hollow camshafts.
    The other two bearing journals on each cam have one drilled hole that is also slotted.

    Everything else appears to be splash lubricated.

    Oil returns down the cam chain tunnel and two other holes at the front of the head.
  7. bmwroadsterca

    bmwroadsterca RadioFlyer

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    F800 oiling system

    oiling_system.jpg
    Pallisti likes this.
  8. Pallisti

    Pallisti Adventurer

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    Excellent picture there, so no oil flow through the tensioner. Thought number 3 is a bit suspicious as well, as the rattle when warm could also be caused by a worn tensioner leaking thin oil.

    It would be nice to have numbers for the chain wear, length for 20 links or so...
  9. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    Purportedly BMW has a wear measuring tool but no one can find it in the list of special tools.
    @JoelWisman had a spec. that did away with the need for the tool by measuring total cam system wear thru the tensioner hole.
    more wear = a bigger dimension from mating surface for tensioner to back of chain tensioner guide....
    but due to Joel's sudden departure from BMW St. Louis ... the data (from him at least) is lost... :-(
  10. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    Question on locking the flywheel.

    I have the official BMW locking pin (it was surprisingly cheap).
    I've heard the feature on the CRANKSHAFT <edit> describes as a v-grooved slot.
    My bike 2009 model (seems to?) has a counter-bored hole instead of a slot.

    anybody else noticed that little anomaly, or am I just being to damned OCD again?
  11. dpike

    dpike BeeKeeper Supporter

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    hm. my '09 f8 has the V groove.
  12. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    Well... Sh*t...............

    So here's a pic from earlier in this thread with what I think the v-groove:

    upload_2020-10-5_14-44-13.png

    I'm going to pull my locking screw out and check but ... I'm 99% sure that's NOT where I'm locked... I'm in a round counterbored hole ...
    I missed it the first time and had to go around again...

    and yet... as shown in my pic. above I had proper cam alignment when I took it apart?

    https://advrider.com/f/threads/d-i-y-cam-chain-replacement.727687/page-22#post-40971718

    Could I be 180 (crank) degrees off? 18


    Anybody got a picture of the other "half" of the crank from the left side of the engine?

    Ahhhhhhhhhhh MaGoo ... you've done it again... :(
  13. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    Update:

    "I've wasted time, I've wasted breath, I think I've thought myself to death"
    Kongos:

    Ok ... So I am currently "intentionally homeless" and as such am working on my bike in a rented storage bin and the lighting is "less than ideal".
    I'm here now and frankly I don't see how I could have done it wrong... it must have been a trick of the light..
    I just checked (again) The pistons are at TDC and when I took the cams out the E and I were aligned in the center,
    and the pin IS engaged in some feature of the crankshaft.

    Looking at the pic. of the crank I don't believe there is anything other than the proper slot that it COULD be engaged in...
    The slot is the only feature on the bob-weight, and if the bob-weight wasn't in front of the anchor hole there would be nothing but air...
    and nothing for the bolt to engage....

    So ... I'm going to shut up now and start drinking early for having though myself to death one more time...
    Please don't tell @Reaver this problem I have is something he's warned me about "several" times....

    :photog

    Thank you all for being my virtual pals!
  14. Reaver

    Reaver How Did I Get Here?

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    Nice try Magoo.

    whether you’re right or just old, remember that you have one of the first F658’s sent to the USA so your mileage may vary.
    JRWooden likes this.
  15. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    Indeed ... Initially I hesitated on buying an early-VIN bike,
    but this critter has been the best money I ever spent ... (perhaps with perhaps a few minor exceptions)
    I hope (and really think) I have the locator in the right place...
  16. bmwroadsterca

    bmwroadsterca RadioFlyer

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    I think this resolves the ambiguity about the TDC tool and where it engages.

    TDC Tool Insertion.png
  17. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    Thanks!
    I have it it the right hole and all that, it's just not clear that my engagement point
    looks like the one that the arrow in your picture points to...

    I'm going to "assume" (yeah I know) that I'm good as even though mine may not look like that there are no other "features" on the bob-weight that would confuse the issue of locking @ TDC.

    Ordering parts today ... will back my way out of this mess once they arrive.................:rayof
  18. batica

    batica n00b

    Joined:
    Oct 2, 2020
    Oddometer:
    3
    Location:
    Serbia
    Hello friends!
    Master link for original BMW camshaft chain wanted.
    Please give advice...
    Thanks!