#3 cylinder holding only about 1/2 the compression of the other three... Cause?
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Thread: #3 cylinder holding only about 1/2 the compression of the other three... Cause?

  1. #1
    Team No Team Array
    Join Date
    Jul 2002

    #3 cylinder holding only about 1/2 the compression of the other three... Cause?

    Bike was stolen and recovered. ICBC didn't determine if there was any engine damage. Number three cylinder later was found to be fishy. Some lack of power, but still smooth, runs fine. 99 gixxer 600.

    Possible causes?

    Head gasket?
    Threw a rod?
    Blew a rocker?
    Messed up valve?

    How much to fix?

    How much to rebuild?

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  3. #2
    Registered User Array J1k's Avatar
    Join Date
    Jan 2003
    do a leakdown test it'll help pinpoint the problem.take off the oil filler cap also,crbs and exhaust to see where its going.you will alweays have it getting by the rings so you'll here a hiss from the crankcase filler.but see if its getting by the valves.

  4. #3
    I'd rule out a thrown rod or blown rocker right away because that would make so much noise itsn ot even funny.
    In theory it could be a leaking head gasket, if so compression pressure could be escaping past the fire ring(metal part of the head gasket around the cylinder) into water jackets, look for bubbles in the coolant. In theory it could be a crack in the head or block but i kinda doubt it.
    Could be a chipped or burnt valve(especially likely if the motor was over revved to hell)
    a cylinder wall could be scraped or something and pressure would escape past the rings, or something could be wrong with the rings.
    J1K is right, you got to do a cylinder leakdown test and find out where pressure escapes, and you'll have a much better idea of whats wrong.

  5. #4
    Take it to i.c.b.c. and keep hassling them...........good luck persistence pays off...........

  6. #5
    rain? whats that! Array REVELATIONS's Avatar
    Join Date
    Nov 2002
    SV 1000s
    Yeah but knowing ICBC, they will say
    "it was like that BEFORE the theft".....

    Now suppose you had a car instead of a bike that got stolen and you had passed aircare recently, now you go back to check and you fail (likely caused by a burnt exhaust valve).
    THAT would be the kind of proof that ICBC couldnt dismiss easily..

    Again.........the whole situation sucks A's

  7. #6
    Chronic Array PRSmechanic's Avatar
    Join Date
    Aug 2002
    2011 VStrom 650, 1983 KZ750, 2006 WR450, and any racebike I can get my hands on!!
    Suggestion; if you have a regular shop you use, get them to help hassle ICBC. If you make it easy for them to say 'get lost', you know what they'll say! Besides, some people try and pull fast ones on them, and they might just put you in that group untill you prove otherwise.
    Were there any estimate/repairs done? That's someone who should stepping up to help, if there was.
    As your bike is reasonably new, and has a rev limiter, you should stand firm, get ready for some B.S., remain polite, but don't take no for an answer.
    chicken strips are a sign of intelligence
    unless you're at the track ;)

    DO IT!

  8. #7
    Registered User Array rdduke's Avatar
    Join Date
    Aug 2002
    04 Ducati Multistrada
    When you did the compression test, did you check the valve clearances first? This is often overlooked. I bought a bike with a "blown" engine for cheap a few years back, and all it ended up being was the owner had let the valves get so tight that they wouldn't close properly causing a very low compression reading. $10 for new shims and I rode that bike to the Artic Circle and back.

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