Compression.

Discussion in 'Softail Models' started by ausibatla, Oct 25, 2013.

  1. ausibatla

    ausibatla Member

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    G'day again fella's. Having only just bought this bike I was wondering if someone can tell me what the compression should be on a 1340 Evo. I have a workshop manual from when I had my 1993 Springer which I am now using for my '88 Springer. The manual claims it should have 90 PSI. I thought that was pretty low. I did a test on the bike and it read 190 PSI for the front cylinder and 192 PSI for the rear. Have the people who printed the manual missed the 1 on their claim of 90 PSI or would the 90 be the minimum you could get away with. Nowhere in the book does it say what it should be.

    Would also like to know if you can trace the year of a 5 speed tranny by its number. Number is 91174099.
    Any advice is appreciated.
    Cheers.
    :bigsmiley23:
    :AUSTRALIA
     
  2. Hoople

    Hoople Account Removed

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    I have never owned an EVO but I agree, 90 sounds low and is probably the min number it can be. Stating that low a number gives them a nice window of error. As long as the engine can tolerate higher compression without detonation, the higher the better (within reason). 190 is about the limit for today's engines running the fuels of today. Back in 90's the fuel would tolerate more spark advance, more compression and higher cylinder temps before problems would appear.

    If the engine doesn't detonate and cranks good, I would be ok with those numbers. I would guess the average stock EVO maybe has 150 psi of compression(?).

    Others that have owned EVO's may chime in.
     
  3. ausibatla

    ausibatla Member

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    Thanks for that Hoople. I appreciate it.
    Cheers.
     
  4. Breeze3at

    Breeze3at Well-Known Member

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    My '92 service manual states "if compression is 90 psi or above, and not more than 10% difference between cylinders, compression is considered normal".

    Last comp. check I did, I think I was above 180.
     
  5. ausibatla

    ausibatla Member

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    Breeze3at, thanks for that. It sounds about right and seems to be about the same as most other bikes. The 90 P.S.I. in the book threw me the way it was written. I'm happy with the 190 readings I got now.
    Cheers.
     
  6. BUBBIE

    BUBBIE Well-Known Member

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    Sounds good to have a USED buy that shows that much compression... Compression = Power... and a good motor to hold it.

    Evo's are a great bike motor... I Loved my 1997 FXDS...
    Virtually Problem Free...

    Just let it warm a little BEFORE ridding off.... Never had a problem with mine..

    Some did have a problem with heads and gaskets and most was from Not warming it up properly Before riding.. (heads/valve covers, warm to the touch)

    Take care, enjoy that bike and YES the ccc = between your two cylinders is Great...:D

    signed....BUBBIE
     
  7. ausibatla

    ausibatla Member

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    Thanks for the advice BUBBIE. I'll do as you say. I see that you're not that far from me. I'm guessing Esperance way.
    The bike has been rebuilt and customised with just 1984 miles on the clock. It has a Queensland compliance plate so I suspect it's an import. I tried to post some photo's but I don't think they worked out. When I signed up I put up my Photobucket site but it doesn't work either.
    If you, or anybody else, can let me know how to post some photo's I'' try again.
    Cheers.
     
  8. BUBBIE

    BUBBIE Well-Known Member

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    ausibatla,

    I think you need a few more post count to do those things on the forum...

    Maybe a Moderator or knowledgeable member will answer you here...

    I used to ask a mod to post a picture or two from time to time and it worked out okay... Maybe one will Volunteer :lolrolling

    I am happy with what I have NOT learned to do here,,, Picture posting is one of them...:s

    signed....BUBBIE
     
  9. dolt

    dolt Senior Member Contributor

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    Once you have enough posts, just select the image you want to post in Photobucket, click on the star/gear in the upper right corner, then click on "get images" and the image options will open. Click on the last image option and it will show "copied". Return to your post and "paste" the image where you want it in your post. Preview your post and you should see the image.

    I don't know why but sometimes the image option in Photobucket does not show as "copied" when the option is selected. Should this happen, just right click on the option and copy/paste the image into your post. Doesn't happen often but does on rare occassion.
    [​IMG]
     
  10. ausibatla

    ausibatla Member

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    Thanks dolt. I'll give it a go ,
    Cheers.