1971 CT70 Rear Shocks

Discussion in 'Tech Area' started by Beretta, Jun 11, 2020.

  1. Beretta

    Beretta Member

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    Finally got it running today- Took for a spin and it rides like a hard Tail- Any suggestions on these rear shocks- are they Hydraulic ?
     

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  3. OLD CT

    OLD CT Well-Known Member

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    Yes there is oil and a seal in them, but they are only sprung for a rider 100 pounds or less.
    If you are 170 or less, dratv on ebay has a set that is stiffer than the originals and are the closest match to original in ruby red. Here is the ebay item# 383536927969 There is a best offer option, Offer him 50 shipped and I think he will accept. I have a set on a bike for awhile and they are pretty good if you really want to keep the stock look.
     
    #2 OLD CT, Jun 11, 2020
    Last edited: Jun 11, 2020
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  4. Beretta

    Beretta Member

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    Thanks !!
     
  5. scooter

    scooter Well-Known Member

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    The hard tail ride is probably the result of a bent center shaft and not rider weight. I’ve seen plenty of them while doing a rebuild where the shaft is bent enough that the shock is frozen and won’t move.

    The math says if you put more mass on a good set of shocks the ride will feel a little softer (I.e. the time to bounce down and then back up will be a little longer). The difference in the response or natural frequency of those shocks with a 100lb rider vs. say a 170lb rider isn’t going to be drastic. Remember you have to add in the weight of the bike when you do the math which makes the extra weight difference a much smaller factor. Also you need to distribute the mass across four springs and include a square root as well

    Think about when that bike was new and those rear shocks were good and you weighed a 100 lb and you offered to give your 100 lb friend a ride on the back. That bike didn’t all of a sudden become a hard tail as soon as he got on. No, it did just the opposite, the ride became a little wilder with the bumps seeming to take longer to settle down. At least that’s the way I remember it
     
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  6. red69

    red69 Well-Known Member

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    Nice to see an informed response from someone that has experience rebuilding those pieces.​
     
  7. scooter

    scooter Well-Known Member

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    Just to follow up - just received 4 shocks to rebuild from a member and 3 of the 4 are completely locked up and the 4th has limited travel - all caused by a bent center shaft
     
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  8. scooter

    scooter Well-Known Member

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    2A017FF3-8F76-45B9-B927-314B8D862CB7.jpeg
     
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