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Thread: Manual cam chain tensioner thread pitch

  1. #1
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    108

    Default Manual cam chain tensioner thread pitch

    Looks like another manual cam chain tensioner thread!

    I pulled the nut off the manual cam chain adjuster on my GS1150 racebike. The adjuster isn't marked, but I suspect it's APE. Red aluminum plate, adjustment is via flathead screwdriver.

    The nut was a #!&!#% to remove from the adjustment screw; it took so much torque to get it off it felt like it was by design (like the valve adjusters on my 1966 Dodge ... no locknuts, just a "semi-interference" fit between the adjustment screw and the rocker arm).

    I'm looking to get a replacement nut; anyone know the thread pitch? My gauge says 20 threads per inch, and the nut I took off of it fits fairly well on a 7/16"-20 test bolt. If the threads are metric they don't appear to be either 1.25 or 1.5.

    Both the nut and the adjuster are a bit boogered, so before I chase the threads on the adjuster with a die I want to make double-sure I've got the right pitch.

    Any suggestions appreciated.

    Related, am I right in thinking I can simply remove the adjuster to clean it up? The red aluminum plate holding the adjuster is attached to the cylinder with two socket-head cap screws, it'd be easy to remove. I suspect the "foot" of the adjuster just pushes up against a blade-style tensioner, so there's no harm in removing it. But figured I'd ask before I just start pulling things.

  2. #2
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    108

    Default

    I called APE, they report 16 TPI for their 'standard' series, and 20 TPI for their 'pro' series.

    20 TPI squares with my measurements, so I'm going to proceed with a thread chase unless someone convinces me otherwise ...

  3. #3
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    108

    Default

    Ended up running a 7/16-20 tap through the nut. Threads onto the pusher perfectly now!

  4. #4
    Join Date
    Apr 2005
    Location
    APE Willow Springs, Ca.
    Posts
    645

    Default

    We don't make ant screw driver adjusting tensioners. Ours have APE on them also.
    Speed Merchant
    http://www.gszone.biz

  5. #5
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    108

    Default

    Thanks for the info Big Jay, good to know! APE was just my best guess ...

  6. #6
    Join Date
    Sep 2005
    Location
    Irvine, CA
    Posts
    892

    Default

    Probably a Ward. Think the Top End Oiler is the same maker on that bike.
    The Three Horsemen
    '85 GS1150ES (Current Income Eater)
    '83 GS1100ES
    77 XLCR

    "Never ride faster than you can see. Besides, it's all in the reflexes."
    Porkchop Express

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