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Thread: 2011 RT Adjustable Rocker Arms?

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  1. #1
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    2011 RT Adjustable Rocker Arms?

    I am looking for adjustable rocker arms to simplify valve lash adjustment. Any one know of a source. I think changing the oil cups is ridiculous to adjust valve lash. Not like I have a parts warehouse available to try different oil cups to acieve the desired lash. Dumb design in my opinion. Aren't the older designs equipped with factory adjustable rocker arms?

  2. #2
    Ponch ponch1's Avatar
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    Anecdotally, the shims seem to hold their adjustment longer. I'd rather have shims than the screw adjusters, but that is me. Actually, if they came out with hydraulic lifters, that would be even better.
    My Motorrad
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  3. #3
    Rally Rat
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    I waited a LONG time for BMW to make an overhead cam boxer. I now have one and love it. Everything should stay in tune for a long time.

    I checked the valves at 2700 miles. all 8 were right in the middle of the spec. Throttle bodies were in perfect sync at Idle. Bike has no glitches.

    Some of this is the result of shims and buckets instead of rocker arms and pushrods.

    I will just change the oil every 3,000 miles for the next 10,000 and check things again. So far it keeps running better. It has a LOT more low end and midrange than my oilhead. Smoother too

  4. #4
    Long Range Rifleman
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    Quote Originally Posted by Ponch1 View Post
    Actually, if they came out with hydraulic lifters, that would be even better.
    Concur.

  5. #5
    Cam Killer marchyman's Avatar
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    Quote Originally Posted by Inga2011 View Post
    Not like I have a parts warehouse available to try different oil cups to acieve the desired lash.
    You don't (or at least shouldn't) adjust valves with the semi-sphere shims by trial and error. The shims come in fixed sizes from 4.60 ~ 5.70 mm in .05mm steps.. Measure the current value. If not within range pull the shim and read (or measure) the current size. You now have all the information needed to calculate and order the appropriate shim.

  6. #6
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    If I increase the shim size by .10mm I doubt it would decrease the valve lash by the same amount, given the geometry, so I am skeptical it's that simple, that is why I said trial and error. Good to know the info you gave though. Still looking for adjustable rocker arms, been wrenching on race cars with solid camshafts my whole life and it's a quick and simple adjustment. I think BMW was looking to save a few nickels and turned a few minutes work into disassembling and reassembling of the rocker set up.

  7. #7
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    Sometimes it's best to read the manual

    Dude Just follow the factory instructions for valve adjustment. It will work. Sometimes too much thinking gets in the way of doing a job proper. Shim valve adjustment has been used for high performance OHC units forever. Shims only go out of spec with wear, no lock nut to loosen allowing adjuster to change. The BMW R overhead cam system is one of the simplest I've ever seen on a OHC motorcycle. Does require a little bit of math though. Do not reuse the retaining circlip!
    Will Stagg Central Coast of Commiefornia
    2012 R1200RT (most awesome unit)
    1978 R100/7 (sidecar tug )
    Yamaha TW200 adventure bikes (3) waay fun units

  8. #8
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    Rocker arm

    You are not going to re-engineer the top end of that motor. Buy a low mile Hexhead and adjust valves to your hearts content. It is very simple I think.

  9. #9
    Ponch ponch1's Avatar
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    Quote Originally Posted by wrenchbender View Post
    You are not going to re-engineer the top end of that motor. Buy a low mile Hexhead and adjust valves to your hearts content. It is very simple I think.
    Or learn to live with the shims.
    My Motorrad
    BMWMOA 162849 | BMWRA 41335 | VROC 8109-R | VBA 19

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