400ex wont start...not plugs

[chuckz71]

my 400 will not start, it turns over, and the spark plug is good (tried 3) and its gettin spark, but it will not fire up...if you sometimes hitting the gas while starting, it sounds like a backfire in the motor or carb. I have heard either my motor is blown, or a valve is stuck, but i started messing around inside of it and the motor isnt blown b/c the flywheel moves and you can tell the motor is in fine shape, everything moves like it should. so i am stumped. please help!

[jamienlogan]

Ill have to say something with the valve

[400ex28]

Timing?

[bubba power]

needs a new timing chain it wouldn't hurt to put new gears in it . buy a 450r timing chain 1/2 the price double the strength.:D :D :D

[400ex28]

Originally posted by bubba power
needs a new timing chain it wouldn't hurt to put new gears in it . buy a 450r timing chain 1/2 the price double the strength.:D :D :D


:huh do you mean CRF450 timing chian?