I have a 2012 JD LA140 started using a lot of oil. This is one of the ones with the compromised air filter. A few years back I switched out the parts to use the newer style canister filters. I still was seeing dirt inside the housing with a oily coating that had to be coming from the breather from excessive blowby. I did a leakdown test and one cylinder had 10% leakage the other 50%. I took apart the engine and found the 50% leakage cylinder head had a bit of exhaust leak from deposits under the valve. When I removed the pistons the top ring end gap was 3/4 of an inch so that is a classic sigh of dirt ingestion. Here in central texas I mow in a cloud of dirt dust so it is about as extreme a condition as you can get. Anyway the manual says max taper is .003 and that is what I am seeing exceot and the very top where it goes to about .0035 then the very top looks to have a relief on it. Anyway I have a precision hone and I can hone it straight but I would think to get a good cross hatch the top will need to be at a minimum .004. I wanted to go .010 over but all I see is .020 piston/ring sets. I'm thinking I will just hone the bore straight and round and replace the rings. Has anyone done this and did it work out OK? I will need to hone straight then check bore size. Wondering what the max piston skirt to bore clearance is as it is not in the manual just the max bore of 3.120. Thanks for any help on this. I am also going to need to see why dirt appears to get around the cartridge filter.