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About BerriosYZ

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    TT Newbie

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  • Location
    South Carolina
  • Interests
    Film, Cinematography, Photography, Hard Enduro, Yamaha, 2 Stroke, Rock Climbing, Camping, Hiking, Soccer

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  1. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    Some of the running symptoms prior to failure make sense for this as just before it blew the powerband was erratic as if the two halves of the valve weren't opening together - jerky and inconsistent when and where the power would kick in.
  2. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    Yep. They had the bore done at an off-site vendor and reassembled top-end in shop.
  3. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    Took it back to the shop. Service manager tried initially to give me the run around and tell me that it was likely just seizure due to overheat stemming from water pump issue. I didn't think that was a good enough answer because it didn't explain the gouge in the piston / cylinder. He also told me that we his technician told him about the water pump leak that he told him to immediately shut the bike off and not run it which was different from the info that I was given when I picked the bike up not noting it as critical but saying to keep coolant in it obviously while recommend the pump replacement. I guessed that it should be pressurized. Problem is there wasn't a complete seizure (I could rotate the kick starter with my pinky finger hardly trying) and there was the big perfectly shaped cylindrical round approximately 3mm groove cut into piston so I told him I believe the foreign object caused the problem so eventually he said he'd take the cylinder in to the guy that does the boring for the shop, a third party vendor, and get him to have a look. Thanks for the help and I think is was probably a part of the valve like you said or otherwise something down in the case that came up. I did ask if they open the bottom end up or flushed the crankcase before running it and they said no. ?! I mean why? Shouldn't they at least have checked to make sure things were good down below before putting brand new parts on and firing it up? Anyway they may still end up trying to shove it off on me but it looks like they have some culpability. I appreciate that the service manager is giving the appearance of trying to make it right and offer some customer service. I'll update. I may end up looking to you for the cylinder work if you think this cylinder is serviceable Gary YZDoc.
  4. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    I did not replace the seal but I did fill the radiator, ran the bike and refilled radiator and repeated until level was at the cap. Leak was steady but slow and only while running. No leak when engine not running. Coolant was not empty or low visually looking into radiator nor when emptied after failure through the water pump drain bolt.
  5. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    This is the info from the service report. Description: Engine was seized, likely from overheating as there was no coolant in the radiator. Resolution: Rebuild Top End, Replaced head barrel pins that were missing, replaced numerous bolts and screws that were missing as well. Adjusted carb and test rode. Work done: Wiseco Top End Kit Yam - PK1568 Spark Plug BR8EG - Br8EG Yamacool 60/40 BL 32 - ACC-YAMAC-BL-32 Compression Test - .5hr Rebuild Top End and Clean Power Valve - 4 hrs Cylinder Bore Recommend: Water Pump has steady leak while running and likely contributed to initial engine failure. No warranty on engine work expressed or implied.
  6. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    I haven't taken the piston out yet. About to do that now. It has probably 2 - 4 hours on it since the rebuild.
  7. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    What should I say to the shop? Do I have any recourse or are they likely just going to tell me it's not their problem?
  8. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    Yea - I'm definitely taking it back tomorrow. The rings are intact. The power valve definitely isn't though. And when I took the right side exhaust valve cover off I noticed the thrust plate was broken in half.
  9. BerriosYZ

    Diagnose this Piston / YZ Engine Failure

    I don't know. I took it to the shop after buying used to get it up and running. I don't currently have a way to measure.
  10. Would like to see if someone can tell me what might have caused this failure on a brand new Yamaha shop top end rebuild / cyclinder hone / cleaned reeds / silencer repack. 1998 YZ250