I have a noise coming from my primary. While I'm riding I don't hear anything but when I let off the throttle I'm hearing a whistle sound. As soon as I pull in the clutch, the whistle noise goes away. What are y'alls thoughts on this?

 

How many miles? Sounds like a loose chain.... Time to pull the primary cover and inspect. Do you have factory service manual? If not get one....

 

25k miles I tightened the chain and it got a little better. But it's still there.

 

inner primary bearing, or transmission mainshaft needle bearing

 

Any way to diagnose one from the other?

 

Got any oil leaks? If the inner primary bearing is shot, that seal is usually shot too. Same with the transmission bearing.

 

No leaks

 

When mine did that it was a transmission main shaft bearing starting to go out.

 

Definitely what I am afraid of bro. How did you diagnose it was that and not the inner primary?

 

You have to start taking things apart and have a look.