timing chain problem crf 250
  • mitchreward
    Posts: 4
    Joined: Mon Jan 29, 2018 3:45 am

    timing chain problem crf 250

    by mitchreward » Mon Jan 29, 2018 3:47 am

    Hello,
    I was trying to finis the reassembly of my bike following a change of piston and timing chain on my 250 crf 2013.
    But I can not put the timing chain back on the camshaft sprocket, chain is way too tight.
    Or if I get there (on the sprocket), I can not push back the bearing into its housing to put the camshaft in his normal position ...

    I counted the number of links, 106 and compare the length with the old chain it's ok. \
    I've also opened the lower carter to ensure the chain was properly set around the crakshaft sprocket and yes

    The chain tensioner is at the moment unmounted.

    Help me please, Do you have a trick, is it normal ?
    Sorry for my english.
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: timing chain problem crf 250

    by JimDirt » Mon Jan 29, 2018 8:16 am

    Welcome to the site !! \:D/

    First , you posted in the "Jetting" Forum , this should be in the "General" forum , OR in the "CRF250R" forum , but i will try to help you with this if i can....

    Questions:
    Is the engine at Top Dead Center ?? , and is the cam being inserted with the cam lobes facing UP ?? (the lobes should be facing 2-O Clock position , facing rearwards with the sprocket "notches" staying level with the head) *like this* _ _

    Are the shims properly seated in the valve stem and the bucket seated down all the way ?? , and did you confirm the shims did not get mixed up or left stuck in a bucket and some buckets have 2 shims instead of 1 ?? , this would hold the cam up and not allow it to seat properly

    When installing the chain , did you make sure the Chain Guide is seated properly and not putting tension on the chain ??

    When you install the chain on the cam sprocket you should be able to tilt the cam into position and it should go right into place if everything above is done correctly

    If any of these items are missed that could be the issue , hopefully one of these things is your issue ...... Check and reply back ......
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: timing chain problem crf 250

    by Back2-2 » Mon Jan 29, 2018 10:25 am

    Jim, shouldn't he have the cam tensioner removed not just backed off ? Could be still pushing on the chain ?
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • mitchreward
    Posts: 4
    Joined: Mon Jan 29, 2018 3:45 am

    Re: timing chain problem crf 250

    by mitchreward » Mon Jan 29, 2018 11:30 am

    First thanks guys !

    the cam chain tensioner is totaly removed, not just backed off.

    >Is the engine at Top Dead Center ??
    Yes it is, ont the mark below, and I see the close piston through the spark hole.
    >and is the cam being inserted with the cam lobes facing UP
    Yes As suggested by the manual.

    >Are the shims properly seated in the valve stem and the bucket seated down all the way ??
    Yes checked and anyway the bucket dont event touch the camshaft at the moment

    >did you confirm the shims did not get mixed up or left stuck in a bucket and some buckets have 2 shims instead of 1 ?? , this would hold the cam up and not allow it to seat properly
    so yes

    When installing the chain , did you make sure the Chain Guide is seated properly and not putting tension on the chain ??
    I think so this is the only part I'm not sure in your propositions, This is why I join 2 photos:
    https://data.anons.fr/index.php/s/hHC6mvlQ8syMUFc
    https://data.anons.fr/index.php/s/hHC6mvlQ8syMUFc

    I'm starting to freaking out.. No one knows.
    I will dump more pics in couple of minutes
  • mitchreward
    Posts: 4
    Joined: Mon Jan 29, 2018 3:45 am

    Re: timing chain problem crf 250

    by mitchreward » Mon Jan 29, 2018 11:45 am

  • mitchreward
    Posts: 4
    Joined: Mon Jan 29, 2018 3:45 am

    Re: timing chain problem crf 250

    by mitchreward » Sun Feb 11, 2018 7:59 am

    Finally it appeared that the chain sent by the supplier was too short by 2 links, 104 instead of 106 simply. They sent me a chain of crf250x ...
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: timing chain problem crf 250

    by JimDirt » Sun Feb 11, 2018 3:06 pm

    Finally it appeared that the chain sent by the supplier was too short by 2 links, 104 instead of 106 simply. They sent me a chain of crf250x ...
    Well that would be that last thing that i would have thought would have been the issue :-k ..... Glad you got it figured out , good job !! =DD
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • Aussiecrf230
    Posts: 1962
    Joined: Fri Jan 06, 2006 11:11 pm

    Re: timing chain problem crf 250

    by Aussiecrf230 » Sun Feb 11, 2018 11:32 pm

    Could have been the other way around with a 106 link chain on a bike meant for a 104. That would have caused some carnage if there was enough adjustment in the tensioner initally.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: timing chain problem crf 250

    by Back2-2 » Mon Feb 12, 2018 8:17 am

    There is one to put in the memory banks for future issues.
    Thanks for sharing what you found and good deal on getting to the root of the problem.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200

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