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Using any GSW Special Tools?

Discussion in 'GS Boxers' started by marchyman, Nov 25, 2013.

  1. gr8ridn

    gr8ridn Been here awhile

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    That is correct, henceforth the slight rattle you may hear upon the first seconds of cold engine star up.
    #41
  2. Emoto

    Emoto Sure, why not?

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    Ok, so if we assume that the tensioner spring, along with oil pressure are enough to properly tension the cam chains while the engine is running, then I am left wondering what exactly is addressed by using the special timing-chain tensioner prior to pulling the cams. If the flats of the cams are observed to be in alignment upon reinstallation, then what need am I missing?
    #42
  3. marchyman

    marchyman barely informed Supporter

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    Guess: the flats of the cams in alignment only mean that the intake is timed to the exhaust and vice versa. But is the engine at TDC? You can apparenlyt loosen the cam sprockets and change the crankshaft position while keeping the cams timed to each other.

    Locking the crank at TDC and putting a known tension on the cam chain (assumed to be the same tension the bike will see in normal operation) will put the sprocket at the cam end of the timing chain in the proper position. Then the cams can properly position and torqued to their sprocket. Without applying proper tension to the cam chain you could be off by some small amount.

    Again, that is only a guess based upon looking at diagrams, pictures, and understanding that the cams can apparently be timed ANYWHERE you like, simply by loosening a screw, moving the cam, then re-tightening the screw. That understanding might be wrong which means you've wasted your time by reading this post. :poser
    #43
  4. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    I'm not 100%, but the instructions were clear. I suspect that the lack of tension insures that any pressure on the chain is not released when the cams are removed, but before you remove them.

    Jim :brow
    #44
  5. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    I think, for timing the cams, you are dead on.

    For checking shims the cam chain tensioner can say in play. Removing the cams the tensioner needs to be out to prevent any preload on the cams causing unintended movement when the cams are removed.

    Jim :brow
    #45
  6. Emoto

    Emoto Sure, why not?

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    Are you saying that the crank is going to move on its own? :yikes
    #46
  7. marchyman

    marchyman barely informed Supporter

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    No the crank is not going to move. It's locked. But with a loose chain the sprocket at the camshaft end can move a bit. And that is every bit as bad as the crank moving. I'm going to make up some numbers as an example. Imagine there is enough cam chain slack to give you the equivalence of a 2º difference in crank timing. Imagine that with the stock tensioner installed but the engine not running the cam chain slack gives you the equivalence of a 1º difference. Finally imagine the tool installed and assume that there is no difference in crank timing as compared to a running engine. Which value would you want to use for best engine operation?

    I made up those numbers and with no experience can't say if the difference would even be noticeable under operation. :dunno I am sure that the cam timing would change. I'm not sure how much.
    #47
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  8. Emoto

    Emoto Sure, why not?

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    Ok, I follow your logic and it seems sound to me. I don't want this to sound argumentative, rather I am trying to think out loud here in the hope that it causes you or someone to arrive at the best conclusions.

    Are you saying the crank is locked because we're theoretically using that special pin tool? I've adjusted lots of valves and never had a crank move unless I moved it. Is the GSW definitely in need of that pin or else the crank moves?

    So... if one were to mark the sprocket somehow before removing cams (magic marker? :dunno) and ensured that it was in the same spot when cams were put back in, the cam timing would not change, correct? The cam chain is always going to be the same length (setting aside longterm wear).

    I also wonder what value the chain tensioner tool adds that the standard tensioner cannot, especially if we are marking the sprocket for position.
    #48
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  9. gr8ridn

    gr8ridn Been here awhile

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    If you are marking the gear teeth of the drive gear and cam gears there is no issue removing the cams to do a valve shim adjustment. That will get that job done. Based on my experience and the factory procedure the locating pin(TDC), tensioner tool, and alignment jig are used to precisely check the cam timing when doing a valve check. No extra effort to check the timing this way. If there is any inaccuracy of the crank position or chain slack all this effort trying to check the cam timing is wasted. The cams are infinitely adjustable once the cam drive gear bolt is loosened. DO NOT LOOSEN DRIVE GEAR if you don't have the tools or knowledge.

    The difference in using the spring loaded engine tensioner and the tensioner tool on the cam position is significant. If I get perfect timing results by using the alignment jig tool along with the TDC tool and the tensioner tool the cams are in time. Just changing the tensioner tool with the engine tensioner, the alignment jig does not fit indicating the timing has changed from added chain slack due to the lack of force on the cam chain guide.

    I think the bottom line is if you want to do just the valve clearance part of the maintenance simply positioning the Cams at TDC combustion stroke and marking the cam gears if removal is called for will get you by. If you are not using the tensioner tool leave the engine's spring loaded tensioner in during the valve check/adjustment. The factory procedure has you remove the engine's tensioner, but also has you replace it with the tensioner tool. At the least some sort of tensioner will be needed to stabilize the cam drive sprocket so you aren't adding an additional error point when re-installing the cams.

    The factory valve check procedure calls for the tools mentioned so a cam timing check can be made when checking valve clearance. My left cams were out of time and the valves were all within spec. After correcting the left cam timing there was a huge difference on engine smoothness at idle up to the entire RPM range. Additionally the mild light throttle surging I was experiencing was eliminated. I expect the cam timing will benefit from continual checking and occasional adjusting at the 12000 mile intervals of the valve checks. Cam chain stretch, chain guide wear, and sprocket wear can be slight but with the length of chain involved a little stretch can cause the cam timing to shift. Take the cumulative wear of all these points and the check every 12000 miles could make a difference in the way the bike performs. As I found, the cams timing just a little off can make a big difference in the way this engine performs.
    #49
  10. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    Logic, you have it.

    On all past bikes there is a procedure asking for engine lock, but I have never found it necessary for valve adjustment. I see no reason why it would be different on this bike.:deal

    Jim :brow
    #50
  11. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    OK, after very careful review of the instructions on how to check the valves I have come to the following conclusions:

    Checking the valve clearance is as I said, rotate the motor until the two flats on the cam ends are in alignment. If they align perfectly with a straight edge the bike is ready for adjustment so long as the lobes are facing away from the valves:

    [​IMG]

    TDC is assured if both flats line up perfectly. Further, cam timing is also assured if both flats line up perfectly. However, this is cam timing only in relation to each other. Theoretically cam timing could be off the exact same amount on both cams, appear to be perfectly aligned, and still be off from TDC on the crank. Odds are slim, but it is possible. Valves can be checked and shims changed in either case with no additional ill effects.

    The need for special tools at this point, for regular service with the flats perfectly aligned, is not there.

    IF, however, the cam lobes are not aligned perfectly, then the special tools are necessary to assure cam timing and to reset them. The cam alignment tool is necessary primarily to hold the cams aligned when loosening and tightening the cam sprocket bolt so you do not put stress on the cam gears and chain. The tensioner tool so you can assure the appropriate tension on the cam chain, and the TDC tool to assure proper exact TDC.

    Again, for regular valve checks and shim changes the tools will not be necessary. To adjust the cam timing, you will need them. IMHO, the cam timing should not ever drift once properly set, but time will tell.

    Jim :brow
    #51
  12. oalvarez

    oalvarez Resident Raggamuffin

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    ^ i am learning (granted very little) by following along here. No, I am not tech/mech savvy like the rest of you but this conversation has been helpful.

    Thanks,
    #52
  13. bemiiten

    bemiiten League of Adventures

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    I'm thinking a substitute 8mm pin to lock the engine would be easy to come up with. As far as the tensioner, How about substituting the piston and spring from the tensioner with a plastic tube from a pen, cut at a length that allows the tensioner to screwed back in halfway, removing the slack from the cam chain. Fabing a tool for the cams doesn't look to tough or the cams could probably be done out of the bike with some trial and error and a extra set of hands.
    #53
  14. marchyman

    marchyman barely informed Supporter

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    For what job? For removing and replacing the cams as part of a valve adjustment there doesn't seem to be any added value. However, if you are also checking/adjusting cam timing then read again what gr8ridn posted:

    That tells me it (or a similar tool as posted by bemiiten) is needed.
    #54
  15. poochar

    poochar Adventurer

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    this is the other BMW tool used.....
    (doing the job of JimVonBaden scale in his pics)

    [​IMG]
    #55
  16. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    I agree. I think you could do it that way and get good accuracy. I'd have to look at the tensioner, but likely it could be done something like you said.

    The tricky part of the tensioner, and I think you could use the original one, is to remove the spring (easy) and replace it with a spacer, but what size spacer and will one size fit all?

    #56
  17. NoVa Rider

    NoVa Rider Long timer Supporter

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    [​IMG]

    :clap :clap :clap
    #57
  18. bemiiten

    bemiiten League of Adventures

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    If the cams are not in time, then the tool will not fit. Being the cams are geared together, you would have to remove them to loosen, then use the tool at installation to set the timing
    #58
  19. bemiiten

    bemiiten League of Adventures

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    Being the cams are geared together, and if they are not in time, then the tool will not fit. You would have to remove them to loosen, then use the tool to set the timing and retorque the gears.
    #59
  20. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    :nod Yes, as already mentioned, a few times. You will have to loosen at least one cam bolt to rotate the cams into alignment.

    IF, however, they are aligned, as they usually are, then no special tool is necessary for regular valve checks and shim replacement!:deal

    Jim :brow
    #60