I've had several Yamaha big bears that the push button wouldn't work on. I've found it to be 1 of 3 things usually. One is the motor control unit. Just a small box maybe 1 1/2" by 1 1/2". 2 is the oil temp sensor. If either are bad your neutral lights and all won't come on or anything to let your push button work or didn't with the ones I had the problem with. Neither will keep you from having spark but you will have to jump it off at the solenoid. The last is of course the solenoid and fuses for ignition. Usually if it is one of these your neutral light indicator will work you'll just get a clicking or buzzing noise at the fuse or solenoid. Maybe that will help you, not saying it couldn't be something else. Those are just the 3 things I have come across.
I have a stator from a 98 350 big bear and one from a 00 or 01 400. There is a good chance that it could work for your 400. If that turns out to bw what it is let me know and maybe we can work something out.
post edited by leed1315 - 2010/12/19 17:24:34