Crankcase vent ? 83 250

Do I need to vent it up under the side panel like it came from the factory or can I vent it down with the carb lines.

You can vent it anywhere. I don't like to leave the end of the hose 'up', though, because then anything can run down the hose and get into the motor. That's bad on the trail and could be worse when you wash your bike.

On bikes like these, where the vent is on one side and the chain is on the other, I like to run the hose up over the carb and down the other side, with the end right over the chain. It's a convenient arc... and an automatic chain oiler if any gets blown out of there. You can usually route it along the frame rails and it looks nice and clean that way.

That is a cool idea too. Probably works better to oil the chain than my leaking countershaft seal. Here's another idea; a previous owner of my WR drilled a hole in the airbox, about midway to top on the left side, and inserted the breather hose into the airbox to keep it out of harms way. The downside is that the open hose end still points up so I guess the potential for something to enter the hose is still there, like water when the bike is washed (or swamped). There really should be a 90 or 180 degree fitting of some sort on the airbox wall for this to be a good fix though. One of those things I will eventually get to....

"Trickest" setup I've seen was a guy who used the stainless steel braided hose and all the fancy fittings. He put a bulkhead connector through the front wall of the air box next to the carb with a 90 degree elbow on each side. The outside was plumbed to the crankcase vent and inside the box was a very cool little K&N style filter/breather hanging down: Vented, filtered, covered, AND pointing down!!

Ya Babay!

Something to think about....
As the bike warms up it'll spit stuff out. When it cools it will suck a little stuff in.. Not much admittedly but some... Put it wherever you like but maybe put a little filter on the end?? Just a cheapy auto one or something? The big up and then down to 'lube' the chain does a similar thing. Goose neck and all that.... remember the biology experiments at High school???
FBC