hey guys i bought a 01 400ex that was blown up and the guy had started to tear into the motor.. i rebuilt it got it all back together and it cranks great great compression and so on but no spark to the plug. tried new plug checked the ground wire on the igintion. still nothing.. i pretty much took the whole wiring harrnes out in one piece so nothing should be plug in wrong but no garentee.. the only thing i changed that would do anything electrical was i put a sparks key in it. it has stock exhuast no aftermarket cdi, 10:1 weisco piston, new head valves so on. but nothing major and nothing that should mess with the electrical..since it ran fine when i was blown up idk what would have changed on the electrical while it was sitting getting rebuilt... so any ideas plz let me know

thanks stone

i had a 400 that had no spark, tured out to be the spark plug boot. were the wire meets the boot had to cut it apart and fix it there. maybe give that a try. good luck hope this helps

also I have seen the coils go bad often you might just want to replace it