Confused About Camhead Valves

Discussion in 'GS Boxers' started by Britome, Jun 13, 2013.

  1. Britome

    Britome Get Free

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    I've done multipler valve adjustments on multiple pre 2010 GS bikes. My 2011 GSA was good to go at 11k when I had the dealer do it. Now at 22k I'm on it myself.

    However, I'm not finding much info on the process. I'm not excited about finding "spheres" or "shims" that I'm not even sure I need let alone the exact size.

    What is your experience in the real world?

    Who needed to re-shim their valves at 24k?

    Any pictorial you would guide me to other than... http://sanjosebmw.smugmug.com/Other/Tech-pictures/10976964_bHf66#!p=1&n=10 ?

    I am doing the COBDR in one month and am tempted to just leave the valve cover as is and don't mess with them. I appreciate your counsel.
    #1
  2. lkchris

    lkchris Albuquerque

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    Mortals can accomplish this task so there's little need for fear.

    It happens a lot that people post to forums to ask for "permission" to ignore BMW service specifications, but doing so is in fact never a good idea.
    #2
  3. Britome

    Britome Get Free

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    I completely agree. I'm just confused as to why there is no info I can find on this including where to find the "spheres" or "shims." Where are the "how to" pictorials an videos that are normally present? I can normally find anything relative to maintenance on these things but this black hole of info is confusing.
    #3
  4. Lensgrinder

    Lensgrinder Long timer

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    I changed one exhaust shim at 6000 miles because mine were too close to the high limit.

    There are two methods to check these,
    1. You can use go/no go with feeler gages.
    2. You can use feeler gages to find exact gap.

    I used method #2 as I wanted to know what I had to work with.

    I rounded the inches. .300mm is actually .0118" .400mm is actually .0157"
    .130mm is .0051", .230mm is .009"

    If you go with #1, you can check with a .012"(.300mm) for the go, .015"(.400mm) for the no go on the exhaust valves.

    For the intake, .006"(.130mm) for the go, .009"(.230mm) for the no go.

    It's so easy, there is no reason not to check them.

    You can get the feeler gages needed at any auto parts store.

    JVB has a video you can buy which will help you do it right.


    http://www.advrider.com/forums/showthread.php?t=596959&highlight=valve+clearence
    #4
  5. def

    def Ginger th wonder dog

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    If you have serviced valve lash on boxers, then I don't understand your question. Remove the OHV covers, measure the valve clearances cold and install shims (spheres) as needed. The process is so simple.
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  6. bobbybob

    bobbybob Long timer

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    I just finished my 3rd valve check at 30K. There was no need to re-shim, same as the 2 previous checks. That being said, I would worry about it if I did not check them. Can't imagine you wouldn't worry also.....
    #6
  7. Britome

    Britome Get Free

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    Very true. Duh! I don't know what I was thinking. Believe it or not, I am a maintenance freak. Thx for the clarity.
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  8. TUCKERS

    TUCKERS the famous james

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    I think shims are easier than tappets/whatsits.

    Measure. If it's over add the overage to the shim size already installed and you have your shim size. They are never under.
    Just measure them all first, then remove/leave and replace as needed.
    #8
  9. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    Get the JVB Camhead DVD if you feel unsure. It lays out the basics for you. The smugmug pics seem pretty obvious to me but Jim`s video will put your unease to rest.
    #9
  10. Rob-Roamin

    Rob-Roamin Knees in the breeze

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    I am just about to check mine for the first time and am looking for a supplier where I can buy the shims

    I haven't enquired at my local bmw dealer as I don't generally buy parts in Australia due to the cost (usually twice the US and UK prices)
    Can anyone advise?
    #10
  11. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    Sorry mate...dealer only as far as I know. Here's the plan to follow.

    1. Make up a chart where you can detail the valve clearances/installed shim heights for the left and right cylinders, intake and exhaust, upper and lower.

    2. Pop off the valve covers and measure the valve clearances and note on chart. Remove the cam followers and note the shim height associated with each valve.

    3. On the out of spec valves, add/subtract the amount of clearance error from the shim height you noted. This will be the shims you need to order.

    4. Button her all back up and continue to ride while you order the parts from the cheapest supplier ($6.48usd at Max BMW in the states). Order LOTS of spare retaining rings (circlips) while you are at it.

    5. Put in the new shims, check clearances again, revise your chart and you`re good for another 10,000kms. Now when you do your next check, you will know what size shim is on each cam and you can just order the correct shim based on your records.

    Cheers!!
    #11
  12. Britome

    Britome Get Free

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    This is exactly why I started this thread. I have never heard if anyone who has ever needed to do anything after checking (part of my knowledge base is the most local bmw dealer). I also can find nothing on how to shim and where to find shims, spheres, etc.

    Big thanx to Billdonna. You get the guru of the week award. I seriously appreciate it.
    #12
  13. Rob-Roamin

    Rob-Roamin Knees in the breeze

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    Thanks Billdonna

    I will check out Max BMW once I have determined what I need
    Might also ask the local dealer to see what the Aust $ cost is per shim
    Regards

    Rob
    #13
  14. Rob-Roamin

    Rob-Roamin Knees in the breeze

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    Just completed the valve clearance check and found one out of spec and another on the limit

    Left side exhaust top 0.4mm / bottom 0.42mm (spec 0.3 to 0.4 mm)

    Left side intake top 0.2 mm / bottom 0.17mm (spec 0.13 to 0.23 mm)

    Right side exhaust top 0.37 mm / bottom 0.37 mm

    Right side intake top 0.19 mm / bottom 0.15 mm

    I pulled both the left side exhaust shims and they both measured 5.25 mm (I only have manual non-digital vernier calipers so this measurement could be slightly out)

    The motor has done 28000 kilometres
    I now have some questions that hopefully someone can answer??

    As the motor wears will the valve clearance gap increase or decrease?

    Is a "standard" dimension shim installed in each cam follower when the motors are assembled in the factory or is each valve clearance set within spec by installing the appropriate dimension shim? (Ie. are the machining tolerances accurate enough to use a standard shim)

    Do replacement shims come in 0.05mm increments?

    Are the shims sold individually or as a kit and what dimension shims are available around the size I have measured (5.25mm)? ( I can't seem to get the MAX bmw parts micro Fisch to work)
    #14
  15. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    Ok, lots here.

    1. As a tool and die maker I can tell you verniers are not accurate enough for this job unless you are very good with them. The good news is BMW etches the shim size on each one around the diameter. Very small, but it's there.

    2. Generaly speaking, as the valve settles into the valve seat, the gap will CLOSE UP.

    3. Shims are not standard, every one will be different from the factory. This is why I advise one to make a map of the shim heights at the time of your first check. Trust me, you'll be glad you did.

    4. 0.050mm(50 micron) steps

    5. No Kits , sizes run 4.6mm - 5.7mm
    #15
  16. JimVonBaden

    JimVonBaden "Cool" Aid!

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    Easy to check the size: [​IMG]

    Very easy to change.

    Jim :brow
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  17. Rob-Roamin

    Rob-Roamin Knees in the breeze

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    Thanks again

    I hear your advice about documenting each of the shim dimensions for future reference

    I don't have a bike lift and decided not to dismantle the intake followers as they were in spec and a little difficult to access with the bike at floor level

    Looks like I will be removing the exhaust shims again today - if I had known the dimension was printed on the shim I could have saved myself some work!

    Live and learn
    #17
  18. Rob-Roamin

    Rob-Roamin Knees in the breeze

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    For those who may be interested
    I decided to take Bill's advice and removed all of the valve adjustment shims to record the dimensions for future reference

    this is what I found

    Right intake top 5.4mm / bottom 5.45mm
    Right exhaust top 5.275mm / bottom 5.225mm

    Left intake top 5.35mm / bottom 5.4mm
    Left exhaust top 5.175mm / bottom 5.15mm

    The variation in shim dimensions confirms that each valve clearance has been set at the factory using a specific dimension shim (in 0.05mm increments??)

    I am a little puzzled by the need for shims with an accuracy of 0.005mm when the specification allows a range of 0.1 mm (eg 0.3 to 0.4 mm) and the accuracy of the valve clearance measurement process wouldn't detect a variation of this order of magnitude

    I will buy 5.2/ 5.225 / 5.4 mm shims to correct the left bottom exhaust and to tweak the left top exhaust and right bottom intake to better spec
    #18
  19. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    Not too hard eh?? Welcome to the self service club!!

    Where does the 0.005 spec come from? From a technical standpoint, gauging accuacy requirment is nominally 1/10 of the tolerence. So for a spec of 0.3-0.4mm, the tolerence is 0.1mm. The required accuracy of the gauge would therefor be 0.01mm, but 0.005mm is overkill.

    Shims come in 0.050mm steps eg. 5.200, 5.250, 5.300. You will not find 5.225 shims.

    Using the exhaust clearances of 0.3-0.4mm as an example, use 0.350 (mid point) as your target clearance. Then pick the correct size shim to give you that clearance. If the shim you want is not available, go the next size down to give you a clearance of 0.375. Remember, valves usually settle down and the clearance tightens over time.
    #19
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  20. Britome

    Britome Get Free

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    Just when I start to understand this, I get confused again.
    #20