Hey man, kak news for sure, sorry about that misfortune. I have recently been doing a RM250 rebuild which isn't the same thing but spark and was a problem and we had to fault find ALL the electronics some things I noticed that might be worth checking:
1. Disconnect Kill switch to see if that solves it.
2. Test the coil for current, takes a few minutes and is quite simple
3. The stator was totally stuffed on mine and from no specific event from when it did to didn't start, pic below of the condition. You can recon these with a good auto electrician or buy a new one, I recon'd mine.
4. CDI is worst case scenario but they typically don't go, check that last.
5. We ran every cable from start to finish and found some worn areas which were patched up or replaced.
Hope running through that helps, can't check much more than that list hey....