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Rare early (June 1976) GS750 cam chain tensioner - different than later 77 & on

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    Rare early (June 1976) GS750 cam chain tensioner - different than later 77 & on

    Has anyone ever encountered a different style cam chain tensioner than the standard style that Brian Wringer has written up in his cam chain tensioner seal/o-ring rebuild tutorial (on his web page)?

    Yesterday I took parts carbs off of a very early 1st week of production June 1976 manufacture date GS750 in the salvage yard. The owner has been trying to push the sale of it semi-complete but untitled at present, since it's VIN and manufacture date are likely the first week of production of 750's in '76, VIN is 102##, around the 230th or so GS750 ever built.

    Well, I just realized my buddy's is probably only a week after that one! June '76, VIN # in the 400's and engine # in the 500's!

    The previous owner was a hack job shadetree mechanic, and I have been correcting a lot of poor work by him. Luckily nothing too terrible so far other than him thinking that KZ1000 VM26 carbs that were apparently cleaner or better in some way & could work better than "identical" (NOT!!!) GS750 VM26's with no jetting changes! Luckily it's still has amazing compression and did not burn a hole through any pistons from being off the charts lean on my wideband O2 setup. Had to swap back to 79 GS750 carbs and a 77 rack to get the lever choke setup vs the later cable choke setup. 9,000 mile clean only partially molested bike...
    I went to check the cam tensioner and found the locknut spinning off by hand.. took it apart, realized the locking rod threaded shaft, that normally has an o-ring on it, was much larger o.d. than I had seen, and had no o-ring, was a 3 part deal with a spring and plunger (missing ball bearing((s))? - divots in each piece in the center of where the spring sits), has no o-ring provision (was leaking oil all over), & instead has a sealing washer of sorts which looks more just like a regular bearing or shaft flat rubber/steel seal that is not on a cartridge bearing, and is fairly mangled...



    Has anyone ever ever seen this? Possibly in more unmolested shape than this one to confirm what should be there? I'm probably going to swap the later style off of another engine, but I wanted to raise this question here since I had no search results pertaining to this in my quest so far.
    It seems as if an O-ring or a rubber washer would do better here, but still, oil could leak through the threads, obvious design flaw and highly likely why I have never seen this on even other 77 engines.
    Attached Files
    Last edited by Chuck78; 05-06-2017, 10:18 PM.
    '77 GS750 920cc heavily modded
    '97 Kawasaki KDX220R rugged terrain ripper!
    '99 Kawasaki KDX220R​ rebuild in progress
    '79 GS425stock
    PROJECTS:
    '77 Suzuki PE250 woods racer
    '77 GS550 740cc major mods
    '77 GS400 489cc racer build
    '76 Rickman CR1000 GS1000/1100
    '78 GS1000C/1100

    #2
    The June 1976 early cam tensioner locking rod/bolt diameter from engine # 550-something vs a later '77 model engine # 27960-something cam chain tensioner...



    With the lack of thread sealing provisions, it's no wonder I have never even read of this style, as they likely immediately realized due to warranty oil leaks early on, that this was a poor design, & promptly changed it!
    Attached Files
    Last edited by Chuck78; 05-06-2017, 06:59 PM.
    '77 GS750 920cc heavily modded
    '97 Kawasaki KDX220R rugged terrain ripper!
    '99 Kawasaki KDX220R​ rebuild in progress
    '79 GS425stock
    PROJECTS:
    '77 Suzuki PE250 woods racer
    '77 GS550 740cc major mods
    '77 GS400 489cc racer build
    '76 Rickman CR1000 GS1000/1100
    '78 GS1000C/1100

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