Well, I thought i'll go ahead and start this thread for anyone that's curious.
I've started my engine assembly and i've been documenting it.
In case anyone wonders why you would do this, it has been said that this drastically improves overall performance of your engine, giving it more torque thru-out the powerband.
First your going to need to locate a complete 83-87 YZ250 engine. You can either use the whole YZ engine or just the components related to the power valve, which is what I did. It works the same either way.
The first part neccessary to swap is the crank gear, if you choose to use the Tri-Z lower engine. The gear off the YZ is a double gear used to operate the power valve governer.
Next you need to install a bearing in the Tri-Z case for the governer. These are still available from Yamaha for $11.00