Wr400 screeching sound from motor

7 replies to this topic
  • R_Little

Posted May 04, 2005 - 12:24 PM


Will riding in the woods my Wr sometimes develops a rattle that crescendos into a loud schreeching noise that sounds like the cam chain is tearing into the head or something.

After it scares the heck out of me, I shut the bike off,,,restart and all is well

It happened last year once and happened again Sunday twice during an enduro.

I just pass it off as the radiator cap opening up and letting off steam but I could use some reassurance my motor is not going to blow up!!!

Anyone got a similar issue?


  • Cedric

Posted May 04, 2005 - 01:32 PM


I would get in there and take a look before it becomes more serious. Your radiator cap should not make a screeching noise.

  • bluebike1999

Posted May 04, 2005 - 04:12 PM


are you sure it's coming from the motor?
I recently heard a screeching that i thought was either the top of the motor or radiator and freaked sh#t. I pulled over and it stopped. when i took off again it was right until about 30 kph then it started, real evil sound. turned out to be a wheel bearing. strange thing is it has buggered my speedo somehow, made the needle fall off the hub in the actual speedometer. vibration maybe?
hope it as simple as something like that.

  • Gadsen

Posted May 04, 2005 - 06:33 PM


I'd make sure the camshaft isnt starving for oil. There is a little service bolt in the head to losen, you can see if its oiling. Screeching is a very expensive sound!

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  • Chris_from_Oz

Posted May 05, 2005 - 06:00 AM


I'd make sure the camshaft isnt starving for oil. There is a little service bolt in the head to losen, you can see if its oiling. Screeching is a very expensive sound!

Good advice here. Definitely undo (don't remove, just back off) the top banjo bolt on the oil feed line to the top end. Start engine briefly, to make sure oil is pumping to the top of the engine. This should be checked at each oil change.....

  • 5valve

Posted May 05, 2005 - 06:59 AM


my inlet cams were overtorqued from previous owners mech
they rotated for several (100?) miles like that
curious for YZ timing I noticed cam doesnt rotate freely (when chain tensioner removed)
rotation areas on the head and the cap were mangled and darkened
oil delivery, as though constant was for sure minimized due to the lack of space, since oil hole squirts directly into those areas

the lack of oil I believe doesnt affect the cams instantly, I also didnt hear any strange sounds

but I do recomend a head cap removal for inspection and check those wheel bearings too :)

  • R_Little

Posted May 05, 2005 - 08:04 AM


I don't think its the cams.
I already had a tight cam journal fixed by edco. I ran it on the highway in the cold and I guess the journal tightened up. I caught it before it got real bad. Mike Crowthers machined the bearing a bit looser and all has been well.
I think!!!

Anyway, I'll pull the cams just to be sure.


  • Dan_from_HB

Posted May 05, 2005 - 08:12 AM


If you've already had cam problems, I'd look there first. It could be a spun main bearing as well. It's hard to diagnose from 3,000 miles away, LOL! When there's a screeching sound from the motor, lots of things can happen and most of them are bad.


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