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  1. #1

    GP1200R HELP-Suggestions

    I am looking for some ideas on what went wrong. I have a 2000 model that has run perfect for years. Last weekend, the center cylinder went out - no fire. Removed plug and the tab was bend over touching the electrode. Look like it was sand blasted too. So, I pulled head to look. It appears the cylinder go so hot that it started melting the piston top as well as the dome in on they head. See pic. The cylinder wall is not in bad shape but does have a few scores. I have no clue why that happened. What would make that cylinder do that. The front and rear cylinders are fine, just the middle has the problem. Oil lines are all attached and had the line popped off the middle cylinder, the walls would have been scored horribly - not the case. Is it possibly a water circulation issue? Hard to believe as the water enters through the head surrounding all cyclinders and out through the individual exhaust port. Still need to take of the exhaust pipe that connects to the cylinders to check for blockage but I am stumped. Any help/suggestions appreciated.
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  2. #2

    Join Date
    Jun 2011
    With the electrode bent on the plug you had to have some thing solid go through your motor which was probably the lower rod bearing coming apart or the carb went super lean melting the piston.

  3. #3
    Just took off head and noticed a small part of a port flange had broken off. I have retrieved the piece with a magnet in the bottom of the block. I assume this is what smashed against the spark plug. Still don't know why the cylinder went super lean. Guess I need to take the carbs off and have a look.

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