ive got a 1980 el tigre 6000 500cc l/c and cant get spark. Ive replaced spark plugs, got new cdi, tried a different ignition coil, and put on a used magneto from a similar sled. was told this other magneto was good but im not sure, is there any tests i can do to be sure this mag is working properly? And is there any other possibilitys? ive also heard that a bad crank seal could cause this, but that dont make since to me as it has ok compression. Please help me!