yeah i have a 2005 400ex with a hmf slip on exhaust with a uni filter stock jets, i know i need to rejet it but thats not the problem, the problem is that it wont start. I just had the starter rebuilt and I'm getting good spark and fuel b ut the neutral and reverse light wont come on and cant get it to crank with the button but it will crank when i cross the silnoid over..Any ideas whats wrong?

 

Dont anyone on here have a clue what could be causing any of my problems on my 400ex??

 

Bad button? Loose connection somewhere?

 

ok i got the neutral light and reverse light on and everything is working now fine , it is cranking but it still will not start. Could it be the valves or a dead spark plug? what do u guys think?

 

You could check spark plug but i don't see how it could be valves unless you ran it with a broken tensioner or was off on timing that will bend your valves and it wont start. Mabey you should jet it and then try.