Victa rotomo, backfiring,has been rebuilt by a competant man ran well a the start. I gave him new rings the piston to my eyes was shagged,he reckoned it was ok, iam thinking its getting blowby the rings, i am using it to mow, or maybe a carby problem.qu does anyone know where to get a new piston, its pure folly to want to mow with such ancient machine, but i dig it. Any help would be appreciated. Its also a model two. Sorry i couldnt find where to put new posts.