i had that issue when i did my carb swap too but my fix was easy, cycling the key on and off a few times then "SHA ZAM!" i hooked up a spark plug test light inline and that is how i found out just cycling the key worked. if i dont get spark, i just cycle the key and then it works. ever since i swapped in a yoshimura push button start i havent had an issue. i check my stock switch and it had zero issues so i dont believe that was the fix, just coincidental.i would work my way backward from the plug, to the coil then so forth.make sure your battery is fully charged as well. time to pull out that test light, good luck.