Compression check
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  1. #1
    Senior Member elime's Avatar
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    Jul 2010
    San Jose, CA
    I did a compression check on my TW's. The one I ride a lot is 143 and the parts bike is 148.

    A quick search came up with some different results others have gotten:

    Silverhead got 160.

    Goofy Footer 135

    macbig2K1 says 128 is good.

    Does anyone know for sure what it is supposed to be?
    Long live the internal combustion engine!

  2. #2
    Senior Member jbfla's Avatar
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    Jul 2010
    FL. GA, NC
    Hi Tony,

    I don't think there is one specific number.

    From experience and research , 100 psi is the minimum for proper combustion.

    Generally, anything between 125 to 150 is considered good, although I've seen some higher.

    2018 Triumph Street Twin..............2016 CB500F
    2014 XT250 ..................................2008 H-D Softail Deluxe
    2008 SV 650..................................2007 DR 650..

  3. #3
    Senior Member silverhead's Avatar
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    Apr 2013
    Central Iowa, USA
    The service manual mentioned that anything north of 150 was 'a problem.' Mine was 160 (as read on two different testers.)

    I should check mine again now that I've ridden the bike about 250 miles since I purchased it. It might have had a ton of carbon in the combustion chamber. My bike's running fine and I'm not hearing it ping on 87 octane, non ethanol gasoline, so I'm happy.

    Most stuff will run even with compression under 100 PSI. To me it sounds like both of your bikes are A-OK.
    1993 TW200

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  5. #4
    Senior Member Leisure Time Larry's Avatar
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    Jul 2012
    Wet-ern Washington
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    2004 TW200, 13-55 gearing, Shinko 241, Race Tech Emulators, Procycle front springs, Works Performance rear shock, Emgo handguards, Luckybike mirror risers, Ken Sean DS foldable mirrors, 30mm Tusk bar risers, Seat Concepts, Kick Starter kit, Plasti-dip camo coat, Cycle Pumps, Ricochet Skid Plate, flood and spot LED pod lights, Sena, Garmin etrex 20 GPS, IMS 313114 folding shifter

  6. #5
    Senior Member elime's Avatar
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    Jul 2010
    San Jose, CA
    Quote Originally Posted by lrppcer View Post
    Read this.

    That is what I was looking for. I even posted in it twice!

    OK then, 128 good, range is 114 to 149. I am golden!!! Thanks.
    Long live the internal combustion engine!

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