My kfx has a K@N air box cover , rev limiter, uni air cleaner, and a Yoshi exhaust manifold and pipe. I can't read the jet # that was put in buy montclare Yamaha. It runs just fine but on low speeds its a little ruff. When I go up a large sand dune it backfires shifting from first to second, and so on. I thought the carb was dirty so I cleaned thoroughly . no change. I'm thinking wrong main and idle jets. Does someone have a similar set up that can tell me the correct jet sizes. (stock carb )