well i did an oil change yesterday for the first time on the bike, a 250 ninja. when i drained the oil pan there wasnt alot of oil that came out, i just assumed it was low on oil. so i drained it all and put in a new filter and out two quarts of oil in. and added a little bit of oil stabilizer. i was riding it today and when i got back from the parking lot there was an oil spot under my bike. i took off the side fairings to see where it was coming from and it came from a black plastic thing located behind the fuel tank. When i clean the plastic thing i saw the hole where the oil was coming from. it looked man made and wasnt like a crack or anything. So what im guessing is that i really didnt drain all the oil from the get go and i added too much and it drains itself to prevent extreme damage. does this sound right? anything would help. thanks

 

I don't think two quarts of oil is too much. Actually, two is not very much at all. Most motorcycle engines can inhale about 4 quarts.

Do you know how much oil you drained?

 

do you have a manual?
My 650 takes 3 quarts. I wouldn't be surprised if your 250 only needed 2 quarts.
Leaking oil however seems out of place to me.

 

is that little black thing an air box? if so then you are getting blow back, which usually occurs if the engine has a tad to much oil... there may be an O ring that has hardened up on you allowing some seepage, but it is not worry about unless it gets on your back wheel. we are only talking about a few drops on the ground right? check your oil level accurately and you should be okay. unlike cars most motorcycle engines are pressurized when in operation, so this can happen... but it shouldn't be allot of oil

 

i didnt drain too much, but i did some googling and i think it is blow back. i drained some more oil to make it at the right level. but it was leaking pretty fast at first i'll say half a cup. thanks for the fast response guys!

 

I have a ninja 250 also, It takes 1.9 quarts. Also that black thing behind the fuel tank is your intake. Check to see if the hose is connected to it right below the carbs.

 

Those little Ninjas only take 1.9??? Whoa. Learn something new everyday.

 

ok now something else is wrong now. the bike sounds a bit weird and has a really low idle. what i plan to do after classes today is take out the air cleaner box and clean that whole thing since the oil was leaking from there. then i'll check the spark plugs to see if they're still good. Is there anything else i should check? thanks

 

check if the vacuum hose out of the carbs is not kinked, this always screws my bike up and causes low idle then stalling. It a clear plastic tube. Also don't adjust the idle screw until the bike is full warmed up