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125cc cam chain tension problems

Discussion in 'Ask the Tech Masters???' started by locko90, Jul 21, 2018.

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  1. Jul 21, 2018 #1

    locko90

    locko90

    locko90

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    I go this 125cc china engine for 50 bucks and it was in pieces. It had a broken sator pick up from the chain coming off and snaping it off the sator plate. seemed that engine was fixable.

    So im in the process of putting it all back together and apon taking the sator off i noticed this spring that supposed to keep tension on the cam chain tensioner was off the tensioner arm.

    So i have putnit back on the tensioner arm but it dosnt seem to be a very reliable cam chain tensioner set up, surely this spring just sitting on the cam chain tensioner arm isn't how it is supposed to be?

    Is there a missing part to secure the sping to the arm or is it just supposed to sit on it like in the picture.

    20180721_111109.jpg

    20180721_111113.jpg
     
  2. Jul 21, 2018 #2

    Eyles

    Eyles

    Eyles

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    I don't know anything about this engine but do know that the way you have it now the spring is not exerting much pressure on the tensioner arm. The spring should be mostly compressed unless the chain is completely worn out and I am guessing there is some other part missing that captures the base of the spring and causes it to be in a more compressed state.
     
  3. Jul 21, 2018 #3

    Eyles

    Eyles

    Eyles

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    I don't know anything about this engine but do know that the way you have it now the spring is not exerting much pressure on the tensioner arm. The spring should be mostly compressed unless the chain is completely worn out and I am guessing there is some other part missing that captures the base of the spring and causes it to be in a more compressed state. Also don't think the spring would engage with the tensioner arm in such a flimsy way? I think there is something missing at the arm end as well? Are you sure this is the correct spring?
     
  4. Jul 21, 2018 #4

    Eyles

    Eyles

    Eyles

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    Further to this. I had a look at the Lifan downloads on the DHZ site and it seems you are missing the whole tensioner assembly. Dunno what that spring is actually for?
     
  5. Jul 22, 2018 #5

    locko90

    locko90

    locko90

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    Yeah i had a look at a lifan 125 (not sure what brand this engine is) and it looks like im missing a few peices.. hahaha! i could pull the engine bottom end and have a look as i might be inside lol.

    On second thought Would i be able to buy this part separately from anywhere?
     
  6. Jul 22, 2018 #6

    xLOCOx

    xLOCOx

    xLOCOx

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    ummm there should be steel rod in between the tensioner arm and spring.......
    should have a rubber tip too, that it faces towards the tensioner arm, so no metal on metal contact is made!
     
  7. Jul 24, 2018 #7

    headsmess

    headsmess

    headsmess

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    yes, there is a part missing. a steel rod.

    and not just any old steel rod, it has holes in it in specific places, and i ground/polished to fit in that hole. they operate on hydraulics. the spring is just there to keep some marginal tension when the rod is replaced and the engine hasnt been run.


    once the oil pump builds pressure, the rod pretty well much locks itself in place.

    should be easy enough to track down. hell, i have a shed full of them here.

    if you do start it without the rod, not only will the tensioner chew itself out, but the oil system wont build any pressure... both are undesirable.
     

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