There are many aftermarket and homemade breather vent relocation mods available to move the vents out of the air cleaner.

There has been debatable ways to route the vent lines off the heads when doing air cleaner mods.
However, exact line routing comes down to function over fashion.
While it may look better or cleaner for the lines to be routed above the air cleaner;
Doing so doesn't make for good functioning of the breather system.

The air / oil that gets blown out is a combination of crankcase pressure and engine blowby.
Blowby gasses produce a corrosive vapor which doesn't need to go back into the engine.
It'll simply pool in the heads / vent lines.

As you can see from the drawings below, expelled air leaves the rocker boxes by running downhill to get out the vent holes in the heads.
If the vent lines are piped above the exit point in the heads, oil out of suspension will not drain back into the engine.
The oil would have to run uphill to get from the heads to the rocker boxes and into the lower end.
So there is no functional advantage to running the lines higher then the head vents.
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The air coming from the head vents has fine oil mist particles in suspension with it.
When that air cools, the oil mist falls out of suspension and collects in the vent lines.
Pointing the vent lines straight into the A/C (OEM) or down into a catch can allows the oil out of suspension to leave the vent lines.
However, pointing the vent lines upward of the head vents allows oil out of suspension to collect in them.
Once there is enough liquid oil in the upward breather tubes it will act just like the trap under your sink.
It may block air from getting out until the engine (on startup) builds enough pressure to push the liquid and bubble up to the top.
So it may affect crankcase pressure slightly until the lines are cleared.
Or the trapped oil may simply be blown out the vent lines in globs.

Vent lines mounted low allows oil to leave the heads.
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Vent lines mounted high tend to promote a mixture of oil and condensation settling near the head connection of the hose.
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Converting breather bolts to vent line extensions

Crankcase vented to atmosphere, while keeping the Screamin Eagle air cleaner.

• Parts:
  • 1/4“ fuel hose
  • 1/4” vacuum nipple
  • 1/4“ vacuum tee
  • 1/4” vacuum elbow

If you look at the base of the air cleaner there is a lug molded on the right side.
A 7/16“ hole was drilled through the lug.
The 1/4” hose has to be forced through the 7/16“ hole creating a tight seal.
The 1/4” hose was run to the bottom of the bike and zip tied out of the way.
The Screamin Eagle air cleaner uses the rubber elbows to direct the crankcase gases into the carb.
These were cut in the straight section and connected the hoses there.
The rubber pieces on the breather bolts are part of the Screamin Eagle air cleaner kit, part number 63520-04.
Other parts can be bought at local auto parts stores. ⁷⁾

This is a SEII air box with new breathers.

• Tools and materials:
  • Drill with 5/16“ bit
  • 2 - breather filters (NAPA part# 6988 or Purolator part# B13153)
  • JB Weld
  • Plastic tubing 5/16” I.D. and about 1/2“ long

Total cost: app. 6 bucks.

The plugged off hole in the backing plate were drilled out.
Both holes were drilled and JB Weld was used to fasten the 1/2” plastic tubing and form the barrel.
Left to cure and later paint. ⁸⁾

The breathers are placed into the barrels.
You may have to remove some more material to ensure a snug fit in the barrel.
There is a lip on the breather housing tube that should be removed also. ⁹⁾