We are having problems with oil coming out of the vent that is supposed to go to the carb. We ran hose from the port to up under the front cover. Is anyone else having this problem. I do know that there is not too much oil in the bike.
I had this issue on my XC, but not on my SX. I think that it has to do with routing it away from the carb. I have not removed the hose from my carb on either of my SX's, but did notice when i routed off of the carb on my 08, that it wanted to push oil out from it.
Over on KTM talk the 530 bike guys have this problem alot, on of them rigged a plastic reservior inline to act like a small catch tank below the carb intake. A clear automotive inline fuel filter works great in this application, this might help.
I know several Yamaha 450 guys who have done this, (throw away automotive fuel filter on the crank case vent line after the black box on the yam setup) to help with heavy breathing when revving the butt out of those engines (sustained 9 - 11K rpm's).
From my Yamaha experince single cylinder big bore engine that rev hard create a truck load of crankcase windage that needs to be vented, and the oil mist associated captured.
The problem with the Yam setup is the black box catch tank sits to low relative to the engine and does not drain the excess oil back fast enough then they start blowing it out of the catch box into the airfilter..........
By the sounds of it what you need is a catch tank on the end of your vent line, basically a box with baffles and a very coarse foam to help condense the oil out of the mist. Isn't there a connection back to the gearbox as well (return drain line ?) on the SX. The bigger the tank the better as the pulse velocity drops off more, but there are limits.
The LTR suzuku has a really nice catch tank stock (black plastic box in front of the engine), look at adding one of those up high behind the radiator maybe ?? or further forward at the steering head area then plumb the return into the engine with a tee to the carb line since having some vacuum on the setup really helps the situation overall for crankcase venting.
Its happened to mine severaltimes in the first two weeks I owned it. I had it spill into the carb and out into the exhaust can. Bullcrap I say. Hasnt happened since then though. I just took off the hose and put a breather filter on it. Seems to be fine now. Mine always happened at start up.