[Jason.MZW20]

That entire pipe in the inset picture is the y-pipe. The pipe detaches a bit after the catalyst.

I was able to move my y-pipe out of the way to replace a damaged connecting rod bearing. Apparently, the bearing rode on the fillet of the crank because I reused the connecting rod bolts ... bad idea for torque-to-yield bolts.

I don't know if that y-pipe pictured will flex enough to move it out of the way. So, just remove the nuts at the end of the pipe and any holding straps/nuts connected to the engine. Then remove the pipe.

Plus you'll get oil all over the pipe even with it moved out of the way. Makes for a nasty drive for a few hours even after cleaning with parts cleaner.

 

[Jason.MZW20]

Again, make sure the PCV system is breathing properly before you start the cleaning process. Looks like some crankcase vapor was coming out of the fresh air pipe with all that buildup.

The breather line also doubles as a passive PCV vent, especially during periods of high blow-by gas volume and low vacuum. The PCV valve is fully open at WOT, but it's limited in its amount of flow, so the breather line acts as a vent as well.