I hate electrical problems - just a poor connection (especially a poor ground) can cause chaos. Note: the coil that produces spark is pretty durable and does not fail very often. The spark plug cap goes bad more often than the coil. The typical sequence of failure is connections, the stator, CDI pickup (or pulse or trigger) coil, CDI box, plug cap, coil and (on rare occasion) the flywheel magnet or rotor. Most of the time the trigger coil cannot be replaced without replacing the stator. However, your TRX250X has a replacable "pulse" coil. Have your mechanic check it. It's about a $25 part.