Motorcycle Repair: 1992 yamaha turbo seca, oil leaks, exhaust side

Question
hello i have a 1992 650 turbo seca ,i have a new turbo ,the check valve is working properly,but it still smokes and drips oil out the turbo,can this be the scavenger pump,or something else , thank you for your time. mark

Answer
Mark,

Did you mean 1982?

-Failure of the oil return line check valve causes this
and can be fixed by removing the line
and cleaning under the ball-check valves.

-there is also a check-valve in the oil line that
feeds the turbo, it is low on the front of the crankcase.  

-This valve has been known to get sticky.  

-This sticking valve allows oil to keep being  gravity fed from
the crankcase to the turbo.  

-The oil then slips by seals and pools in the exhaust
side of the turbo. The check valve is no longer
available from Yamaha, so your only hope is to
attempt to clean it well.

-NOTE: Use caution removing the check-valve.  
The banjo fitting with oil pipe is easily damaged,
and expensive if not impossible to replace.

-the other thing to check is for bad turbo bearing seals.

-does this engine have alot of miles on it? As engine
wear can cause oil leaks. Is the engine breather open?

-uses a Mitsubishi TC03-06A turbo.

Troubleshooting:
http://www.jhdiesel.com/failurechart1.htm