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  1. #1

    2001 GP800R internal engine damage

    GP800R internal engine damage

    Rear spark plug wasn't firing, pulled plug, the tip of the plug was closed, no gap
    did a quick check for compression with finger over hole
    compression seemed good
    tried another plug, couldn't hear any noise, went out for a quick run, came back same thing
    tip was starting to close, plus some small beads of metal around porcelain
    checked compression with tester 120 psi rear, 150 front cylinder
    pulled cylinder head, looks like metal was bouncing around in chamber, top of piston hammered or looks a bit mushroomed in portions of it
    decided to pull cylinder to look for all metal and or what cause might be
    found a flat piece of steel in the very bottom of the crankcase
    plus some of the webing of the case has been chipped off
    best I can determine
    looks like the peice of flat steel might have come from the crankshaft
    Im thinking like one of the crank pin /spacer washers might have came a part
    any others others out there had this kind of situation and or know Of typical faults with this model?

    I was hoping too be able to slip in a replacement piston
    however if it has deeper problems don't want to beat myself up, waste time and money, etc...


  2. #2
    Also have a second craft
    same model and all
    did a comparison for compression
    the rear piston is also lower for compression reading
    called around and spoke to a few yamaha dealers
    one of which warned of these models having issues with rear piston going out
    so now I'm wondering if any others out there have had this issue?
    if so can you suggest which brand pistons to use as replacements
    definately want the repair to hold up


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