Ok so the base gasket on my rear cylinder has been leaking for a while. I got got a noise that kinda sounds like the primary dragging on case. Checked chain and its good. Is it possible for air to be sucked in and mix with the oil thus making noise while going through oil pump? Noise only happens when bike is warm. Clutch in or out and if its in gear or not does not affect the noise. Any
ideas?

 

The noise has nothing to do with the oil leak. Does the noise change with engine speed or with bike speed? If you can hear it when it is not moving, then get a mechanic's stethoscope and try to find the location it is loudest at.

 

It is there with bike on stand. Used scope and its coming from case. Seems loudest right at the center of the V. Thank you

 

It does pick up with rpm but is alot slower than rpm if that makes sense

 

Best way to describe it is like the noise you get walking in wet shoes

 

What year is this bike, how many miles? Lifters can go bad at 50K.

 

Base gasket and noise have nothing in common. Base gasket seeping is common on EVO. Often due to failure to warm it up before hitting it hard. Was more common in early ones . better gaskets and install have reduced that.

 

Bike is a 98 with 65k on it. Lifters hydraulic? Would explain it.

 

For some reason when I think of the wet shoes, It makes me ask about your crank vent backing up with excessive oil, is that a possibility ? Where are you venting it ?

 

Lifters or inner cam bearing. Don't ride it until you pull it apart. I would not even start it until it has been put back together. Inner cam bearing should be replaced with the older style bearing. Lifters: I stick with HD. There are lots of threads on them.