genefewings Report post Posted October 1, 2017 Hi All Im replacing the piston in my 2013 ossa tr280. I am having trouble finding an oem piston kit anywhere. I did notive that there is a s3 racing piston kit available - has anyone had any experience with this kit? I am also replacing the cylinder or perhaps sending the bore away for rechroming. Its about the same price either way- any thoughts? Thanks for your time Gene Quote Share this post Link to post Share on other sites
genefewings Report post Posted October 1, 2017 Great. Thanks for that fantastic advice. S3 piston measurements in the new cylinder should be spot on then? Quote Share this post Link to post Share on other sites
tsiklonaut Report post Posted October 2, 2017 (edited) I just recently put S3 standard (A) into B bore. I have the very high compression (2013) head and also mine tends to run hot often so it's a good choice to avoid seizure and give the engine more "relaxed" operation (less friction) when hot. Just check if you see honing marks on the bore (the around 45-degree oval lines) in the working space of piston, if you see those clearly in reflection and you see no excessively worn spots then you're fine without doing re-boring/re-coating, just put in a new piston with rings. Edited October 2, 2017 by tsiklonaut Quote Share this post Link to post Share on other sites
jacques blackburn Report post Posted September 1, 2019 My 2012 OSSA TRI 280 FACTORY just begin to change sound more like rattling. The engine had never been rebuilt and I fear that it become worn. Before opening I looked for S3 piston and there are 3 size A B C. how do you know if the size of the piston is A or B or C. The engine have many hours on it. Is it difficult to replace the piston? Quote Share this post Link to post Share on other sites
