transmission troubles

[joekdx00]

I own a 2000 KDX 220 and I keep on blowing the inside needle bearing on the left side of the bike opposite of the clutch, on the input shaft. I run 80 weight maxima trasmission oil. Any suggestions would be helpful. Thanks.

 

[jaguar]

That happened to mine (replaced bearing twice) I think because I had an oil leak and occassionally the level would get low while riding hard.
Also make sure the level in the sight glass is at the top of the glass.
Is it leaking oil, and if so, then from where?