i ran my 650 low on oil and it scored the cylinder wall and piston and the local 4 wheeler mechanic told me that it cannot be bored without getting the cylinder nicromed and it would cost about 600.00 to do that. also, it costs that much to get one done online and the piston is another 200.00 plus the gasket set. i may just sell it as is. i did find another 650 H1 with a bad rear axle for 1850. just weighing my options. i may buy the other 650 and use mine for parts and part the leftovers. also seeing if there is any interest in the parts.