My 07 yz450 has a weird noise while revving,it goes away at idle.It sounds to me like something is rubbing or like a dry bearing.I can't seem to remember the 426 I had do the same thing.It maybe normal sounds as it always been in the bike but I only bought it this spring.I hear it while riding and sitting,its like a medium pitch whistle,it will do it in neutral but you have to rev it up some to make it start.I have a skid plate on it and I hear that makes the noises worse,bike runs great and I have never seen any metal particles in the filter,it always comes out clean not even the little aluminum flakes.I'm wondering what the balancer bearings sound like when they get bad.First I thought maybe the timing chain rubbing on the guides,maybe I can get it recorded and post it up.

been searching and found that the straight cut gears make a whirring sound and whirring best describes it,alond with a skid plate and aluminum frame I guess it get amplified.Sort of sounds like wind howling while riding.

changed the oil tonight after a ride and was ready to pull the engine apart if anything looked suspicious.The magnetic drain bolt just had some black filings like you would find in any gearbox,the oil filter came out spotless,I rinsed the filter in a white bottom half oil bottle and after I could only see some very tiny aluminum specs,it was more like dust.Nothing in there that would look like something failing,I guess its just ride and ignore but she seems awful rattly when hot and some of the noise do go away when you pull in the clutch.

What does that link have to do with this post? Grey.


.... some of the noise do go away when you pull in the clutch.

Any time you think you have an abnormal noise on a bike with any aluminum aftermarket skid plate, take the plate off the bike before you make yourself crazy. If the plate has any contact with the frame anywhere except where it bolts on, it will make noises that will make you think the engine is eating itself.

aaahhhh,,, k .... That's for spelling it out for me... All i seen was El Camino and talk about cars and trucks.

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