MC-21 R.....Located in Missouri, so no chance of any outside help here....But, ex wife rode the machine about 2 years ago, she said it backfired loudly a few times then stopped running, it's been in my shop since......Any way to check the coils? If so, what are the readings supposed to be? Any other suggestions? It's been years since I've wrenched on this machine so any help would be appreciated