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Thread: Timing chain replacement

  1. #1
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    Question Timing chain replacement

    '77 R100S had the original endless chain (I think?) with 80K. Replacing the crank sprocket but can't see any typical timing marks. The cam sprocket and tach drive gear do have paint marks but not on the teeth. Looking for some advice.

    Also my plan to reinstall the crank sprocket is to heat it to about 350F (heat chalk) then with heavy leather gloves install it with one quick motion. Have a sleeve and big brass hammer if necessary!

    One last question: How do you use the search function? Very rarely is it much help!

    Thanks
    Tom

  2. #2
    Administrator 20774's Avatar
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    Quote Originally Posted by rolyak View Post
    One last question: How do you use the search function? Very rarely is it much help!
    You sort of have to know what to look for, and narrow your search word down to something that will be found easily and take you to what you're looking for. A bit of a Catch-22.

    I've used the Search This Forum with some success...you might have to wade through a lot of posts and try multiple words. Another way that seems to be successful is using the google utility, something like:

    site: http://www.bmwmoa.org/forum "timing chain"

    which will search the entire forum for the phrase timing chain.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    Registered User stanley83's Avatar
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    Quote Originally Posted by rolyak View Post
    Also my plan to reinstall the crank sprocket is to heat it to about 350F (heat chalk) then with heavy leather gloves install it with one quick motion. Have a sleeve and big brass hammer if necessary!
    This summer I replaced the timing chain and crank sprocket on my R75/6 and found Snowbum's article very helpful.

    He states explicitly "It is important NOT to let the sprocket get over 290??F!!!
    You can purchase 'sticks' that wipe a temperature sensitive coating on the sprocket. Use a 250??F type. Or, heat in oil on the hot plate or stove using a candy thermometer."

    I heated mine in oil in a camp stove and checked with a candy thermometer and it went on very easily.
    Justin in Somerville, MA
    _________________________
    76 R75/6, 78 P200E, 63 VBB
    Lots of bicycles

  4. #4
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    Smile Snowbum's article

    Read this after I posted, very long and very helpful.

    Appears that keyway position will give me correct sprocket position even without marks.

    Thanks to you both!

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