I have read several threads that say a worn out reed valve can mimic an over rich fuel mix condition. In theory I would think the reverse would be true. If a reed valve was failing it would allow to much combustion gasses into the intake tract and therefore lean out the mixture by lowering vacuum over the carb jets. Scavenging in the exhaust tract could also be adversly effected causing more spooge to be sucked back into the cylinder. Fouled plugs? Maybe I am spending to much time thinking and not enough time riding. :yikes: