i have a 2001 400ex and i was riding one day and it wouldnt rev up all the way. SO i shut it off and now it hasnt started since. We drained the gas to see if that was the problem but it did not help. me and my dad think that the timing chain is off or that the valve is bent. we are taking it to a local shop to have it looked at.

If the valve is bent, how much do you think it will cost to fix and how long will it take

 

new valves, problw new springs, and great time to change outthe origional valve seals 4 new ones. OEM valve seals tend to leak... overall mabe a week, mostly waiting 4 parts. but there is a holiday in there si id give it mabe 10 days, if that is your problem

 

What made you think the timing chain was off and a valve bent? Does it have no compression?

 

well what made me think this is that when i try to start it up, the exhaust has suction instead of blowing air out.

 

Yeah, that might not be a good sign...