2000 BB 400.
Started the quad and got wire smoke followed by a blown 10A fuse and it shut off. The wire that fried it’s insulation is the ground wire on ignition coil as well as a small ground wire on the frame ground bolt. (I believe it’s the same wire at different ends)
Found that the problem was bad connection from the battery to frame. Causing all power to be pulled though that smaller ground wire.... I think. Replaced the large battery cable-to frame. Replaced fuse. I believe the blown fuse was a result of that ground wire melting though and contacting a neighboring wire wich has been corrected.
All the lights Come on with the key and the quad turns over but getting no spark.
Inpediance tested ignition coil’s primary and secondary windings, stator & pick up coil. Everything’s within spec. Confirmed ignition coil has good ground as well as the (now bare) ground wire.
Replaced the $300 C.D.I in June after a similar no spark troubleshooting situation.
I have a supplemental service manual witch contains that schematic. The 30A main fuse did not blow. It was one of the 4 smaller 10A fuses. The only fuse in the box that if removed disables the starter and dash lights. All the rest were fine.