oil leak

I just bought a DF250RTC about a month ago and had it out for a ride with speeds up to 60MPH, when I got home the bike was dripping oil and I cant figure out from where. I took off the farings and noticed a black hose on top of the engine connected to a black resevoir with another black hose coming off the top of it and it is connected to nothing. Is this suppose to be connected to something and what is it? Has anyone else had issues with the bike leaking oil after a long ride.

Also wanted to know if anyone has had issues with the speedometer being way off? Speedometer was reading 70 and passed a radar check on side of road and clocked me at 45. Had speedometer up to 90 at one point and was still being passed by cars in a 55MPH zone.

i have the same problem on my speedo and the hose is a breather for the engine as it smells of oil also check your bolts on the engine sprocket cover as bottom bolt may be loose and cause the leak due to vibration

I've had my 250 for almost a month and I kind of have the same issues. With speedometer, and leaking oil. Whenever I change my oil after the first ride I leak oil. I'm not sure what that's about and I can't find where it's coming from all I know is that it leaks from the bottom of my chain cover at the back of the wheel. As far as the speedometer, I'm off as well. It seems like it's 10 miles per hour off. I was looking for a different spedometer but I'm not ready to get one yet. So I just got me a badass Gorman GPS and put that puppy right on my gas tank and I use that to check my speed. And I also used that to find my way back home when I ride with no sense of direction.

The black hose on too is the engine ventilation. When you overfill oil IRS coming out there.
Ventilation is necessary because with every move down of you piston you create a pressure in your engine case. Every move up results in pulling a vacuum. Both need to be neutralised against environment.
Make sure the hose is not twisted or bent and closed because then the pressure Push's oil through the bearings and seal rings. You start burning oil and get leakages.


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That's the reason. Thanks for the help.