Video of bad sound 2004 YZ450F

1 reply to this topic
  • gpshogan

Posted May 01, 2011 - 08:10 AM


Picked up a 04 yz450f. Like showroom new, all orginal. Looks like less than 20 hours, not even frame paint wear. It did puff a little black smoke when its cold, but then it went away. Did that couple times only when cold, minimal amount. Could be old gas.

It was running great, but now has developed a noise from the bottom end.

This noise gets better when the clutch is pulled in, but then it also makes a metal on metal noise every once in while. I took out the clutch plates, to see if it would go away. Ran in just for 5 secs after adding a ton of oil in it. The noise is still there. The clutch basket dosnet seem loose, had a little back and forth play, just hair.

The noise sounds likes it coming from behind the clutch basket. Its not aknock but more a constant thud. Like I said with the clutch engaged it was more quiet.

Every once in while it makes like a metal on metal noise just for a second. A big clue is that when it happened I was in the woods, and the bike would really grab out from a standstill.

(Kind of like when your chain slaps real hard.. ) Like when I went to let the clutch out, it smacked real hard, sounded like a chain slap but could have been internal.

This sounds bad I know. But all the gears work just fine.

Any idea, I dont want to run it till I fix it.

I ran once with just clutch plates out for 5 secs to see if maybe it was something there.

I was going to take the whole basket off and make look behind there.

Any idea?

I really hope the crank or rod are not bad.... But wouldnt the bike have blown up by now...

I rode it 15 mins home in the woods after it made this noise..... still fires right up

All I can say is that when riidng, it felt like a grab going from 0 mph and starting to let the clutch out, almost like the chain grabbed, or brakes were on, then it breakes free and was fine. Only did this like twice.

And the noise in contant, sound like behind the clutch, but could be coming from left and right side. Def more towards the bottom of the motor..

Pulling in clutch helps w noise, but still makes the metal on metal just for a SPLIT SEC when it happens.....

Any ideas??

Crank? main bearing? clutch bearing? Clutch basket? transmission?

This bike has like 20 hours on it

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  • Octanee

Posted May 01, 2011 - 11:21 AM


well its hard to say, the mic is not so good, but i THINK it sounds like a crank, but really i cannot hear too good.....

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