quickbansheeman Posted November 3, 2015 Report Share Posted November 3, 2015 (edited) So I went for a ride and coolant starting leaking out the exhaust, so I just thought it was just an o'ring, opened it up and saw this a dent on the dome, what could of caused it? There's no dent on the piston. I have a 4mil, drag port v force reeds, plus 4 timing and 19cc domes, I was running c12 race fuel. Edited November 3, 2015 by quickbansheeman Quote Link to comment Share on other sites More sharing options...
oldskool Posted November 3, 2015 Report Share Posted November 3, 2015 Looks like a new dome. If the dome was mint when you installed, then something got on top of the piston. You say piston has no mark/scare. When a chunk gets on top of piston and bike has run, it will leave lots of marks, not just one. Are you sure dome was perfect when it went in? 1 Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted November 3, 2015 Report Share Posted November 3, 2015 Looks like a needle bearing from big end rod bearing Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted November 3, 2015 Report Share Posted November 3, 2015 This also don't look like viton orings and could have been compromised with heat in the fire ring area, I would at least pull the jug on that side and check everything out, antifreeze doesn't like to compress like fuel charge does and can put stress on parts Quote Link to comment Share on other sites More sharing options...
Lowroll Posted November 3, 2015 Report Share Posted November 3, 2015 This also don't look like viton orings and could have been compromised with heat in the fire ring area, I would at least pull the jug on that side and check everything out, antifreeze doesn't like to compress like fuel charge does and can put stress on parts the Viton O-rings are the red/brown colored ones correct? 2 Quote Link to comment Share on other sites More sharing options...
quickbansheeman Posted November 3, 2015 Author Report Share Posted November 3, 2015 I'm going to take the jug off today and check the rest out, but what could have caused my o-ring to break and the dome is even bent from the side that the chunk of the o-ring is missing. I purchased the dimes brand new and had them milled for the 4 mil. Quote Link to comment Share on other sites More sharing options...
quickbansheeman Posted November 3, 2015 Author Report Share Posted November 3, 2015 This is my cylinder and the top of the piston Quote Link to comment Share on other sites More sharing options...
quickbansheeman Posted November 3, 2015 Author Report Share Posted November 3, 2015 I'm going to take the jug off today and check the rest out, but what could have caused my o-ring to break and the dome is even bent from the side that the chunk of the o-ring is missing. I purchased the domes brand new and had them milled for the 4 mil. Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted November 3, 2015 Report Share Posted November 3, 2015 x2 Quote Link to comment Share on other sites More sharing options...
quickbansheeman Posted November 3, 2015 Author Report Share Posted November 3, 2015 that mark doesn't look good. On the cylinder walls? Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted November 3, 2015 Report Share Posted November 3, 2015 yea looks like somthing got inbetween the piston and cylinder wall. Quote Link to comment Share on other sites More sharing options...
mike0chek Posted November 3, 2015 Report Share Posted November 3, 2015 ya you got something grinding around in that cyl Quote Link to comment Share on other sites More sharing options...
quickbansheeman Posted November 3, 2015 Author Report Share Posted November 3, 2015 (edited) Just took it apart and found everything in tack, nothing missing, the piston feels and looks smooth, do you guys think it will still run well with the cylinders looking like that? Edited November 3, 2015 by quickbansheeman Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted November 3, 2015 Report Share Posted November 3, 2015 Never mind. Replace o rings and copressiong test it Quote Link to comment Share on other sites More sharing options...
quickbansheeman Posted November 3, 2015 Author Report Share Posted November 3, 2015 I'm just going to replace the dome and then do a compression test, there was a little of shredded aluminum from the dome on the side of the piston. Quote Link to comment Share on other sites More sharing options...
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