top end rattle after a little hard riding?

[CK1999.400ex]

i have a 2007 400ex motor in my 1999ex ,and it started to make some top end rattle after a few laps of hard riding and hi reving on a small mx track i only hit rev limiter once , and it only was for a second ... and then i came to a stop to see what the lap time was and it died .... ??? when i restarted it it was ticking and rattleing kinda loud ... i turnd it of and loaded it in my truck and brought it home ... i took the rocker cover off and dont see any thing wrong ... i think one of the valves was stuck a little cause when i pushed on it it poped up ... any ideas on what it could be? everything is good nothing bent or broke ???

[AZ440ex]

Check your valve clearences and get back to us with the results

[quadbod]

Another easy check would be the cam chain tensioner, mine went a couple of months ago and it sounded kinda like tappets or valves.

[noreversesucks]

Do ya have a way to compress the valve springs by hand?
Sounds like ya might've bent a valve stem or maybe broke a valve spring maybe.
That's about the the only thing I can think of that'd cause a valve to stick.

[Exrider434]

if it was the right side intake valve, it is not sticking open it is the decompression feature in the motor. I had the same thing happen to me when i touched it one time it snapped shut and i was like WTF but i just read through my clymer and it says that it stays open for a little longer than the rest to decompress the motor for easier starting.... Not too sure bout the noise though, check your valve clearances .004 intake and .005 exhaust that could very well be the problem, the 400ex tend to be noisy in the top end

[CK1999.400ex]

hey thanks for the input. i will be looking at it closer to see what i can find out. its about 5 degrees out and no heat in the garage. lol .so i can only stand to be out there for a short time .i will let every one know what else i find .

thanks

Chris

[CK1999.400ex]

it was the tensioner i replaced it and now it's fine



THANKS GUYS FOR THE INPUT AND INFO !!!!!!!