450 running sick.... help!

8 replies to this topic
  • jackhillis

Posted September 09, 2007 - 01:26 AM


hey im hoping someone will be able to help me, i recently purchased a 03 wr450. i have riden a couple of times and the bike seemed to be running ok, i did an oil change and cleaned the air filter yesterday, i took the bike for a quick spin and it would not start so i had to roll start, then it was running like a dog, plus there was a clunking engine noise, would anyone know why it is running like a dog, is it because the battery doesnt have enough charge to keep timing or is it something else? is 1 ltr sound about right for an oil change?
thank you
jack hillis

  • Gandalf_WR450

Posted September 09, 2007 - 11:34 AM


Any chance you got too much oil on your air filter? Ive seen bikes barely run when they over lubed.
Should hold 1.2 liters- that shouldnt be it. Did you get oil seep from the oil gallery bolt?

  • dr x

Posted September 09, 2007 - 12:07 PM


Worth checking the cam timing to see if it has jumped, I bought an 04 and the previous owner seemed to have done no maintenance whatsoever.

When it stalled the timing would jump and then would'nt start again.

Check the cam chain, gaps etc.

good luck, hope its not the timing gear....

  • ophir

Posted September 09, 2007 - 01:04 PM


Check your valves. SOunds like they need to be adjusted. When the Yamaha valves need adjustment, they wear up, thus keeping the valves open, making it hard to start.

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  • jackhillis

Posted September 10, 2007 - 03:29 AM


thank you guys, talked to the guy who owned the bike before me who has been a great help, worked out i was sold the wrong air filter, thank you now i realise that i did oil it a bit much so that may be a reason, i might also check the valve clearances, is that a pretty straight forward job?
thank you again

  • dr x

Posted September 10, 2007 - 02:38 PM


Takes about 1/2 an hour to check the clearances...

Have you got a manual?

  • jackhillis

Posted September 11, 2007 - 03:26 AM


yea i have a manual, talked to the previous owner today, i did over lube the filter apparently, and the clearances he is going to show me how to do it. he said today that he has had to adjust the clearances twice since new. thank you so much for all your help

  • jackhillis

Posted September 11, 2007 - 03:26 AM


thumper talk is so good!!! and its members are even better

  • DB_Cooper

Posted September 11, 2007 - 02:04 PM


Sounds Worse Than Too Much Air Filter Oil...
The "clunking" Noise And Having To Push Start Sound More Like A Sheared Off Flywheel Which Has Now Changed Timing. Very Common On The 03 Wr450.
Cheapie Ez Fix-replace Woodruff Key.
Expensive But Correct Fix-pull Motor And Replace Crank With 05 Updated Unit.


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