themuffinman Posted January 10, 2010 Report Share Posted January 10, 2010 (edited) the bike was running perfect till it seized up on me the day after i got it. I took the cylinder heads off and the left piston has what looks like shrapnel on top of the piston. I cleaned up the shrapnel and the piston itself looks like hell while the right piston looks fine. Anyone know how/why this could happen? Would I be okay with just putting a new top end in the motor or do I need to take a look at the crank and everything too? (i have a general idea of what to do but this is the first time i'd be attempting a rebuild.) Check out the pictures and tell me what you think. I did drain the coolant but for some reason what was in the block didn't come out. help me out here guys. Edited January 10, 2010 by themuffinman Quote Link to comment Share on other sites More sharing options...
blowit Posted January 10, 2010 Report Share Posted January 10, 2010 the bike was running perfect till it seized up on me the day after i got it. I took the cylinder heads off and the left piston has what looks like shrapnel on top of the piston. I cleaned up the shrapnel and the piston itself looks like hell while the right piston looks fine. Anyone know how/why this could happen? Would I be okay with just putting a new top end in the motor or do I need to take a look at the crank and everything too? (i have a general idea of what to do but this is the first time i'd be attempting a rebuild.) Check out the pictures and tell me what you think. I did drain the coolant but for some reason what was in the block didn't come out. help me out here guys. There is a laundry list of reasons why a piston can fail but it sure looks like yours was due to improper port chamfer or hole clearance. If the skirts are all busted up, which I suspect, you need to carefully mic the bores and have a pro inspect the chamfers. BIG cause of unknown engine failures. All that piston crown damage is from foreign objects bouncing around in the combustion chamber, Something let go to get the big chunks up there. Mull Engineering Quote Link to comment Share on other sites More sharing options...
themuffinman Posted January 10, 2010 Author Report Share Posted January 10, 2010 There is a laundry list of reasons why a piston can fail but it sure looks like yours was due to improper port chamfer or hole clearance. If the skirts are all busted up, which I suspect, you need to carefully mic the bores and have a pro inspect the chamfers. BIG cause of unknown engine failures. All that piston crown damage is from foreign objects bouncing around in the combustion chamber, Something let go to get the big chunks up there. Mull Engineering so your thinking the real problem is in the bottom end if there's that much stuff bouncing around up there? Quote Link to comment Share on other sites More sharing options...
blowit Posted January 10, 2010 Report Share Posted January 10, 2010 so your thinking the real problem is in the bottom end if there's that much stuff bouncing around up there? As I said, I am thinking skirt failure from cause of port chamfer or bore size but that is merely a guess not even looking at the engine right now.. With that much Al flying around, you may very well have hurt the crank. Just have to take it apart and go from there. Building without measuring is a recipe for disaster. Important to know what you have... Quote Link to comment Share on other sites More sharing options...
themuffinman Posted January 11, 2010 Author Report Share Posted January 11, 2010 can anyone help me out with why the rest of the coolant won't drain out of the cylinders? Quote Link to comment Share on other sites More sharing options...
79malibu Posted January 11, 2010 Report Share Posted January 11, 2010 can anyone help me out with why the rest of the coolant won't drain out of the cylinders? Theres a 10 mm bolt on the side of each cylinder that will get most of it out. Quote Link to comment Share on other sites More sharing options...
blowit Posted January 11, 2010 Report Share Posted January 11, 2010 can anyone help me out with why the rest of the coolant won't drain out of the cylinders? Because there is not other drain for them other than the drain bolt in the side of each cyl. Most people just remove them and flip them over to drain the jackets. Quote Link to comment Share on other sites More sharing options...
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