I am working on a 400ex for a friend of mine it is getting spark briefly at times, but once i try to get it to fire it loses all spark. He bought all of the electronic pieces excpet for the stator and we tried changing the cdi with no results, then we chand the coil and it immediatly got spark, but died before i could get the quad to fire. Has anyone had simaler experince and know what it could likely be? any help will be much appriciated thanks.