A guy told me that I might have bent valves on my 400ex. Is this possible?

 

i REALLY dont think that it just bend a valve outta no where. the only 2 ways it could is if somethin got under the valve on the seat and kept one side from closin all the way or it was outta time but correct me if im wrong. and i dont think the would come from the factory outta time and with springs too heavy to bend valves when its runnin. have u had any head work done to it?

 

Do you think its possible to have landed a little too hard and the timing chain jumped a tooth and bent a valve. It hasn't ran since the landing yet it backfired and blew the carb out of the spicket.??????

 

the timing chain sits on half the sproket at all time. if u landed hard enough to make the timing chain come ALL THE WAY off and skip some teeth then ur a arms and axel and all that would be bent like crazy. if it bent a valve then the valve wouldnt sit comppletely down in the seat and would not seal and then not let the engine compress, so if u had a bent valve ur ex wouldnt be running. i think the guy that told u that doesnt know what hes talking about.

 

A simple compression check should indicate a bent valve if you have one. It is extremely rare to bend a valve without something else going with it like a timing chain failure, broken crankshaft or overhead camshaft.

 

Check your woodriff (sp) key on your timing sprocket. I havn't opened up this motor yet, knock on wood. But it has happened in a boat I picked up cheep. If you were revving the engine kinda high when you hit, the sudden jolt to the bottom end locking up with the chain having some velocity, inertia, what have you. Can cause the timing key to bend. Hell this happened on my buds lawnmower when his wife hit a rock (boulder). It is the half moon shaped key that the sprocket engauges (probably has one on both sprockets, but dunno). I will throw it off time and keep it from running, or only run at the top end as it retards the timing.