main bearing going out?

[jwmcd1986]

<iframe width="420" height="315" src="//www.youtube.com/embed/zKtltUqtDSk" frameborder="0" allowfullscreen></iframe> not my video but my 400 does the exact same whining sound. mines coming from the bottom end. 3 different mechanics I know said its my main bearings going out. has new clutch, new starter clutch, and oil pump because I thought that was the problem but it didn't fix it so I had my mechanics check out the sound and they said a bad bearing is the only thing that'll make that sound. is there anything else it could be because I'm not trying to split my case

[400man]

might could try pulling the flywheel cover or clutch cover and see if the crank bearings have any play in em?

[jwmcd1986]

they were tight when I changed my clutches and pump. it my be another bearing. thought cam bearings but sound is strictly bottom end

[400man]

hmmm. does it run fine and everything?

[jwmcd1986]

yea it runs great with no issues. just started it and let it idle and noticed after 15 minutes of idle time and warm up, the noise completely disappears. only does it when its cold.