Crf250r dropped valve help

I was riding at the track today my bike sounded like it dropped valve but the crank is locked up. I thought if you dropped a valve it would not lock up the crank. Any info please

piston could've seized


tear it down and go from there there's really no way of knowing without opening it


maybe someone else can chime in

its easily possible if the valve bent and could not go back up through the guide all the way, and the piston being on its way up in the stroke. Pretty much anything is possible in the way these bikes blow up. Take it apart and look.

May have broke a valve head off on the up stroke of the piston, and got the valve head stuck in the head and piston. 

What you can do to check if u crunched a valve without opening it up is put the bike into a high gear, like 4th. Spin the back tire in reverse. If it does u can push on the kicker to wherever it stops and you can conclude it's a dropped valve.

No don't do that. Take the valve cover off and visually inspect.

No don't do that. Take the valve cover off and visually inspect.

Why wouldn't you want to do that? Its not like you're going to cause any more damage than whats already done. If i was in the situation id rip it apart, but if hes not mechanically inclined to do so, its a quick check.

He runs risk of damaging more than what is already damaged. 

Thats all. And It wont tell you much. 

ImageUploadedByThumper Talk1407167732.162221.jpg

Dropped an exaust valve

Nailed it!

Sorry man. Let me know if can help.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now