[Avery Reed]

Hey, still kinda new to forum. Ive gto an '02 400ex that got a few issues. I previously solved a bad key switch, but now i cant get the quad to run because it wont crank well. Battery is definitely charged, fuses are good, grounds are good. When i hit the button, it cranks over like 3 times then stops. I tried jumping it with another battery, no luck. I tried charging the battery, then immediately taking it off and hitting the button, which made it crank faster, but still didn't start, and it made this weird squeaking sound. Stopped cranking within 10 secs, but it sounds like its cranking over smooth and only struggling when on the compression stroke. I cant get the spark plug out to check for things like compression and spark because i don't have the special tool, and my 18mm socket doesn't fit. Does anybody have any idea on what the issue could be? Ive done some reading and people have founds bad cranks, i hope to god thats not what this is.

 

[Whereyeat]

Going through the exact same thing right now and I’ve tried just about everything possible except put a new crank in it. That is next step for me now. Did you figure it out?