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Thread: Throttle Body Synchronization

  1. #1
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    Throttle Body Synchronization

    I have noticed that the F800's do not require a throttle body synchronization (TBS) in their Service Schedule. I'm sure its a dumb question, but why is that?

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    I don't think it's a dumb question...
    I want to know also ...

    It's not on the maint. schedule, and there is no procedure for it (at least that I can find) in the BMW manual either.....

    maybe just the way the throttle bodies are "put together" makes it impossible for them to get OUT of sync. unlike the boxers and other bikes?

  3. #3
    Survivor akbeemer's Avatar
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    Quote Originally Posted by jimbob59 View Post
    I don't think it's a dumb question...
    I want to know also ...

    It's not on the maint. schedule, and there is no procedure for it (at least that I can find) in the BMW manual either.....

    maybe just the way the throttle bodies are "put together" makes it impossible for them to get OUT of sync. unlike the boxers and other bikes?
    Essentially correct. Combine that with being able to safely put the valve checks on a 24K mile schedule and it is a very easy bike to maintain.
    Kevin Huddy
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    Benchwrenching PGlaves's Avatar
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    We got in the habit of synchronizing carburetors on Airheads and throttle bodies on Oilheads because the only connection between the two carbs or throttle bodies was that thin, sometimes stretching system of cables reaching the two carbs or throttle bodies way over here and over there on the other side of the bike.

    We never thought about it on classic K bikes because the three or four throttle bodies were very close together and were tightly mechanically linked with a sturdy linkage. Only after a huge number of miles was it ever necessary to tweak things a little bit by adjusting air bypass screws to somewhat account for mechanical wear.

    That is what is going on with the F twins. Two closely spaced, mechanically linked throttle bodies. I wouldn't worry about them for a hundred thousand miles or so and then I might see what is happening vacuum wise. Voni's F800S is now approaching 80K miles so maybe next year I'll think about it. With a locked mechanical linkage the throttle plate angles ought to stay the same almost forever.
    Paul Glaves - "Big Bend", Texas U.S.A
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    Quote Originally Posted by AKBeemer View Post
    Essentially correct. Combine that with being able to safely put the valve checks on a 24K mile schedule and it is a very easy bike to maintain.
    AK:
    I thought they were still saying valve lash check every 12K? Did BMW change their recommendation or are you saying based on experience you think that BMW is just being too conservative?

    From what I have read they do not need to be adjusted very frequently, typically not needing any adjustment till 50K miles or beyond, but I have also read that unlike some other designs these bikes tend to "use up" the clearance and thus not checking it frequently enough could result in burned valves?

    My twin has about 28K miles on it. The local dealer did my lash check at 12K and reset the computer (and thankfully gave me the check sheet on which the actual clearances were recorded). Later on I bought a GS-911 and found that the engine computer has an internal algorithm for estimating when it thinks a particular engine's lash check is "REALLY" due (perhaps based on time at high RPM or ...???) it reported at about 22K miles that I was not really due until 28K.
    I need to check it again soon...

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    Thanks, guys. Makes sense.

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