pitting/holes in cyinder wall
but I don't see ANYTHING for a cross hatch there, and I think I see what looks to be specs from detonation.
2012 CRF250R #946
"Stop being a dipshit, and we'll both be less aggravated" - GuyB
This is about as good a pic I can get without removing the cylinder, but I think it tells a better story. it actually looks worse in the pic than to the naked eye, and now that I can see it that clearly I am guessing it needs plated. Am I right? And what could cause this condition, partial seizure, lean condition or just worn out? Its a 95 with less than 40 hours, i would guess.
From Millennium Technologies website -
Porosity is gas trapped in the base metal aluminum during casting. These “holes” are exposed when the cylinder is machined or subjected to various chemicals in the plating process. The pits are usually small in size, and in good castings few and far between. When kept under acceptable levels, porosity will not adversely affect the performance or longevity of the engine. In fact, it will improve lubrication. The pits will not cause the coating to peel, nor will a ring hook on them. As far as our specifications on porosity, our cylinders carry a lifetime warranty against defects in materials and workmanship. Therefore, through extensive testing we have found that porosity is a cosmetic problem only. In our pursuit to have both cosmetic and functional perfection we do everything possible to remove these pits. In some cases this is not possible, so we release the cylinder only in cases where it will not affect performance
Sometimes I make jokes, I'm not smart enough to explain them so it's on you if you're too dumb to understand them...
Use a bore gauge and they are not cheap, unless you have a CMM then use that. And yes those are pits from the casting, not from wear, but I always check my cylinder for out of roundness and check the piston for cylinder wall to piston clearance. Measure the piston with a mic at the widest part on the skirt. The piston should come with instructions on wear to measure it and what the clearance should be. That piston looks like a Wiseco which is forged and the clearance would be about .002". Measure the cylinder bore front to back, side to side, both top and bottom.
Cycle Junky wrote: I'll do that, thanks. Its as good a time as any to learn how to measure cylinder wear. I would ask what tool I need and how to do it, but i'm gonna break the mold and google this one on my own :}
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